Miracle-dz/UniFAR-FTUs huggingface dataset:
Erosion and delivery of deposited peat sediment

Erosion of deposited organic peat sediments from peat harvesting ditches was studied in both laboratory and field conditions. Peat sediments were placed in a recirculation flume at controlled pH levels and allowed to stabilize from 15 min to 10 d. Afterward, different flow velocities were applied and the peat erosion was measured. The erosion rate was related to the physical properties of peat: the particle size and form, settling velocity, peat type and degree of decomposition (von Post). The mean average settling velocity for the peat was measured to be 0.87 m h−1. The median sediment particle size was 42 μm, which indicates that the peat sediment is partly cohesive. The deposited sediment formed a loose layer overlaid by more stabilized layers. Critical shear stress for the surface of the loose peat layer was 0.01 N m−2 and for the more consolidated layer was 0.059 N m−2 after a stabilization of three days. The erosion coefficients determined during laboratory study varied between 3.7·10−4 and 4.1·10−6 kg m−2 s−1. The determined erosion and sedimentation rates were used to calibrate sediment erosion and deposition models. A new approach was then developed for the uses of these models to simulate peat sediment delivery from field ditches. The model was tested against measured values which were in accordance to observed sediment transport rates.
Palynology of the Huqf Supergroup, Oman

Abstract Extensive subsurface sampling of the Huqf Supergroup in the Sultanate of Oman has yielded microfossil assemblages of Cryogenian, Ediacaran and Early Cambrian age. Microfossils have been recovered from most stratigraphic units in the Huqf, including Marinoan-equivalent horizons of the Ghadir Manqil Formation (Cryogenian Abu Mahara Group), the Masirah Bay, Shuram and Buah formations of the Ediacaran Nafun Group, and the A3 (latest Ediacaran) and A6 (Early Cambrian) cycles of the Ara Group. Despite the extensive recovery of leiosphaerid acritarchs from the Shuram Formation, there is no indication of the large acanthomorphs typical of other early–middle Ediacaran assemblages. This absence suggests a relatively young (post-extinction) depositional age for the Shuram; however, the signal is complicated by local deep-water conditions and the facies-specific distribution of Proterozoic microfossils. A shallower-water sequence of undivided Nafun Group sediments preserves sphaeromorphic acritarchs in association with filamentous microfossils, fragmentary vendotaenids and possible vaucheriacean algae.
ON THE STRUCTURE OF HURRICANES IN THE UPPER TROPOSPHERE AND LOWER STRATOSPHERE

Abstract A synoptic study of a number of hurricanes at the time of landfall is described with particular reference to the thermal and wind structure in the upper troposphere and lower stratosphere. It is shown that the low pressure core of the mature hurricane, before recurvature, extends not only throughout the troposphere but sometimes protrudes into the lower stratosphere up to about 27 km. , the upper limit of this investigation. The upper core is found to be cold above 15 km. with temperatures occasionally 8°–10° C. below normal at the tropopause Level. A peripheral ridge and a peripheral jet in the upper troposphere are described, and the possible role of these features, as well as of the cold core, in the hurricane mechanism is discussed. It is suggested that the cold core may be caused by forced ascent above the well-known warm core of the hurricane. It is also shown that a hurricane which has recurved and become embedded in the extratropical westerlies may not have an upper cold core and its struc.
Intercomparison of Bulk Aerodynamic Algorithms for the Computation of Sea Surface Fluxes Using TOGA COARE and TAO Data

Abstract A bulk aerodynamic algorithm is developed for all stability conditions for the computation of ocean surface fluxes. It provides roughness lengths of wind, humidity, and temperature for a wind speed range from 0 to 18 m s−1: zo = 0.013u2∗/g + 0. 11ν/u∗ and ln(zo/zot) = ln(zo/zoq) = 2.67Re1/4∗ − 2.57 as derived using the Tropical Oceans Global Atmosphere (TOGA) Coupled Ocean–Atmosphere Response Experiment (COARE) data constrained by other observations under high wind conditions. Using the TOGA COARE ship data and the multiyear hourly TOGA Tropical Atmosphere–Ocean moored buoy data, intercomparison of six different algorithms, which are widely used in research, operational forecasting, and data reanalysis, shows that algorithms differ significantly in heat and momentum fluxes under both very weak and very strong wind conditions, but agree with each other under moderate wind conditions. Algorithms agree better for wind stress than for heat fluxes. Based on past observations, probable deficiencies in r.
CHANGES IN SOIL ORGANIC CARBON UNDER EUCALYPTUS PLANTATIONS IN BRAZIL: A COMPARATIVE ANALYSIS

Proper assessment of environmental quality or degradation requires knowledge of how terrestrial C pools respond to land use change. Forest plantations offer a considerable potential to sequester C in aboveground biomass. However, their impact on initial levels of soil organic carbon (SOC) varies from strong losses to gains, possibly affecting C balances in afforestation or reforestation initiatives. We compiled paired‐plot studies on how SOC stocks under native vegetation change after planting fast‐growth Eucalyptus species in Brazil, where these plantations are becoming increasingly important. SOC changes for the 0–20 and 0–40 cm depths varied between −25 and 42 Mg ha−1, following a normal distribution centered near zero. After replacing native vegetation by Eucalyptus plantations, mean SOC changes were −1·5 and 0·3 Mg ha−1 for the 0–20 and 0–40 cm depths, respectively. These are very low figures in comparison to C stocks usually sequestered in aboveground biomass and were statistically nonsignificant as demonstrated by a t‐test at p < 0·05. Similar low, nonsignificant SOC changes were estimated after data were stratified into first or second rotation cycles, soil texture and biome (savanna, rainforest or grassland). Although strong SOC losses or gains effectively occurred in some cases, their underpinning causes could not be generally identified in the present work and must be ascribed in a case basis, considering the full set of environmental and management conditions. We conclude that Eucalyptus spp. plantations in average have no net effect on SOC stocks in Brazil. Copyright © 2012 John Wiley & Sons, Ltd.
Genome-wide integrative analysis revealed a correlation between lengths of copy number segments and corresponding gene expression profile

Microarray analysis has been applied to comprehensively reveal the abnormalities of DNA copy number (CN) and gene expression in human cancer research during the last decade. These analyses have individually contributed to identify the genes associated with carcinogenesis, progression, metastasis of tumor cells and poor prognosis of cancer patients. However, it is known that the correlation between profiles of CN and gene expression does not highly correlate. Factors which determine the degree of correlation remain largely unexplained. To investigate one such factor, we performed trend analyses between the lengths of CN segments and corresponding gene expression profiles from microarray data in hepatocellular carcinoma (HCC) and colorectal carcinoma (CRC). Significant correlations were observed in CN gain of HCC and CRC (p<0.05). The trend of the CN loss showed a significant correlation in HCC although there was no correlation between the length of CN loss segments and gene expression in CRC. Our findings suggest that the influence of CN on gene expression highly depends on the length of CN region, especially in the case of CN gain. To the best of our knowledge, this is the first study describing the correlation between lengths of CNA segments and expression profiles of corresponding genes.
Les déterminants de la santé subjective dans les pays baltes au cours des années 1990

After the collapse of the Soviet Union, the Baltic countries experienced abrupt changes in life expectancy. This study focuses on self-rated health and its possible determinants, taking advantage of the Norbalt Living Conditions Surveys carried out in 1994 and 1999 and of the Estonian Health Interview Survey carried out in 1996. Using structural equation modeling and directed acyclic graphs, the similarities and the differences were examined among the three countries both in the values of the parameters of the model and in the sample populations? prevalence rates. A major result of the study is the remarkable stability of the model whatever the country, year, gender or age group.
Extension and uplift at Alba Patera, Mars: Insights from MOLA observations and loading models

High-resolution Mars Orbiter Laser Altimeter (MOLA) profiles of the large shield volcano Alba Patera call for a critical reexamination of models for the growth and evolution of this volcanic edifice. An extensive system of graben cuts across Alba Patera, extending from Ceraunius Fossae to the south to Tantalus Fossae to the northeast. In the vicinity of the edifice, the otherwise generally north-south orientations of these graben are deflected to circumferential directions. MOLA topography reveals that the circumferential graben are located well up the flanks of Alba Patera. Both the type (extensional) and location (midflank) of faulting on Alba Patera are inconsistent with the state of stress predicted for purely surface-loaded flexure models. To constrain the conditions governing the evolution of Alba Patera, we employ finite element models for the volcano and lithospheric stress field under a combination of loading mechanisms. Buoyant sublithospheric loads (representing underplated magma, low-density mantle residuum, or dynamic support from mantle convection) and intralithospheric displacements (representing sills “trapped” by horizontal compressive stresses in the upper lithosphere) can generate the observed midflank slope breaks and circumferential extensional fault zones at radial distances comparable to that of the subsurface load's characteristic radial extent. Both mechanisms moderate stresses in the upper lithosphere in favor of continued magma ascent. However, bottom loading requires a disk-like load geometry and an elastic lithosphere thickness Te sufficiently small to allow the load's shape to be apparent in the surface deformation (Te ≤ 32 km). Such low Te is inconsistent with Mars Global Surveyor (MGS) gravity and topography data. In contrast, intralithospheric sill complexes can produce the observed topography and faulting at Te values consistent with those inferred from gravity and topography (50 ≤ Te ≤ 100 km). For these conditions, principal stress orientations on the lower flanks are also consistent with the orientations of lower-flank graben, provided that faulting was induced by dike intrusion or tensile failure rather than shear failure.
On the preparatory processes of the M6.6 earthquake of June 17th, 2000, in Iceland

A model is proposed to explain the spatial distribution of foreshocks of the June 17th 2000, Ms 6.6 earthquake in the South Iceland Seismic Zone (SISZ) and the high stress drop of the mainshock. Fluids of magmatic origin, ascending at near‐lithostatic pressure through a low permeability layer perturb the regional stress field, inhibiting fluid flow laterally, where a high strength asperity is left. The asperity is modeled as elastic, embedded within a medium with low effective rigidity. Regional stresses due to tectonic motions are perturbed by the presence of the asperity, enhancing the production of hydrofractures and foreshocks in the NW and SE quadrants and increasing considerably the shear stress within the asperity, leading to the NS striking mainshock.
Time‐Dependent Strength Gain in Freshly Deposited or Densified Sand

Much evidence is now available that freshly deposited or densified saturated clean sand may exhibit substantial stiffening and strength increase with times up to several months. Sand deposits may undergo a significant loss in strength as a result of disturbance, thus behaving in some respects in a manner similar to sensitive clay. These phenomena appear to be related to solution and precipitation reactions involving quartz, amorphous silica, and other compounds and the formation of cementing bonds at interparticle contacts. The effects of these phenomena must be considered when evaluating the results of laboratory tests on reconstituted samples, in the assessment of ground improvement using deep densification, in the evaluation and interpretation of relative density measurements, and in the estimation of liquefaction potential.
Millennial-Scale Climate Variability During the Mid Pleistocene

[1] We use the oxygen isotopic composition of planktonic foraminifera Globigerinoides ruber (white) from Ocean Drilling Program Site 1058 in the subtropical northwestern Atlantic to construct a high-resolution (∼ 800 year) climate record spanning the mid-Pleistocene climate transition (∼410 ka to 1350 ka). We investigate whether or not millennial-scale instabilities in the proxy record are associated with the extent of continental glaciation. G. ruberδ18O values display high-frequency fluctuations throughout the record, but the amplitude about mean glacial and interglacial δ18O values increases at marine isotope stage (MIS) 22 (880 ka) and is highest during MIS 12. These observations support that millennial-scale climate instabilities are associated with ice sheet size. Time series analysis illustrates that these variations have significant concentration of spectral power centered on periods of ∼10–12 ka and ∼5 ka. The timing of these fluctuations agrees well, or coincides with, the periodicities of the second and fourth harmonics, respectively, of precessional forcing at the equator. An insolation-based origin of the millennial-scale instabilities would be independent of ice volume and explains the presence of these fluctuations before the mid-Pleistocene climate transition as well as during interglacial intervals (e.g., MIS 37 and 17). Because the amplitude of the millennial-scale variations increases during the mid-Pleistocene transition, feedback mechanisms associated with the growth of large, 100-ka-paced, polar ice sheets may be important amplifiers of regional surface water hydrographic changes.
Global hydrology 2015: State, trends, and directions

Global hydrology has come a long way since the first introduction of the primitive land surface model of Manabe (1969) and the declaration of the “Emergence of Global Hydrology” by Eagleson (1986). Hydrological submodels of varying complexity are now part of global climate models, of models calculating global terrestrial carbon sequestration, of earth system models, and even of integrated assessment models. This paper reviews the current state of global hydrological modeling, discusses past and recent developments, and extrapolates these to future challenges and directions. First, established domains of global hydrological model applications are discussed, in terms of societal and science questions posed, the type of models developed, and recent advances therein. Next, a genealogy of global hydrological models is given. After reviewing recent efforts to connect model components from different domains, new domains are identified where global hydrology is now starting to become an integral part of the analyses. Finally, inspired by these new domains of application, persistent and emerging challenges are identified as well as the directions global hydrology is likely to take in the coming decade and beyond.
Soils: A global sink of atmospheric carbon tetrachloride

Analysis of soil gas from the world's major biomes indicates that carbon tetrachloride (CCl4) uptake by soils is a ubiquitous process. The global flux of CCl4 from the atmosphere to soils was estimated to be 27 ± 21 kilotons per year (Kt yr−1), corresponding to a partial atmospheric lifetime of 90 years (yr). The total lifetime of CCl4 in the atmosphere, taking into account the stratospheric, oceanic and soil sinks is estimated to be 20 yr. The recently identified oceanic and soil sinks of atmospheric CCl4 suggest that current emission estimates of CCl4 may be underestimated by ∼60%.
Stable isotopic signature of a palaeoaquifer, Mississippian Alamogordo Member limestones, Sacramento Mountains, New Mexico, USA

Nine stratigraphic sections, each ≈5 m thick, were sampled from the Alamogordo Member limestones of the Lake Valley Formation, Sacramento Mountains, New Mexico, USA. Four stratigraphic sections consist entirely of lime mudstone and wackestone, whereas the other five sections have a prominent layer of crinoidal packstone about 1 m thick at their base. Stable isotopic analyses reveal that the lime muds in the sections with basal packstone layers show a downward decrease in δ18O and constant δ13C values, whereas those in the sections solely composed of lime mudstone and wackestone have, in general, relatively uniform δ18O and δ13C values. The diagenesis of the Alamogordo Member limestones was previously believed to have been governed by the downward percolation of meteoric water from a regional pre‐Pennsylvanian exposure surface ≈100 m above this unit. However, the uniform δ13C and downward decrease in δ18O values in the lime muds in the sections with basal packstones indicate that the meteoric water ascended within the Alamogordo Member, rather than descended from the overlying exposure surface. This indicates that the basal packstones were probably a conduit for meteoric water. This is further supported indirectly by the relatively uniform δ18O and δ13C values of the lime mud in the sections without basal packstones. The implications are that the oxygen isotopic gradients may be used to identify palaeoaquifers, flow directions within these aquifers and that meteoric diagenesis below an exposure surface could be governed by flow through a palaeoaquifer.
Semiannual cycles of pollution at Bermuda

To identify the sources and determine the transport pathways for aerosol during the Atmosphere/Ocean Chemistry Experiment (AEROCE), we examined the temporal variations of trace elements in daily aerosol samples collected at Bermuda from 1988 to 1994. Crustal (e.g., Al) and marine (e.g., Na) elements showed annual cycles with summer and winter maxima, respectively. In contrast, pollution-derived elements (e.g., Sb) showed unusual semiannual cycles with strong spring maxima and weaker fall maxima, which to the best of our knowledge, have not been previously documented. The seasonality in trace element concentrations was mainly transport-driven: The spring maxima of pollutants were caused by rapid westerly transport from North America, and the fall maxima were caused by North American air slowly transported to Bermuda by large high-pressure systems that stagnated over the lower mid-Atlantic states. Low concentrations of pollution elements in winter resulted from the southwestward extension of the Bermuda-Azores high-pressure system that brought marine air to Bermuda from the east or northeast while hindering transport from North America and Africa. The summer minima in pollutants were associated with air transported from the eastern Atlantic and Africa. The variations of the trace gases O3 and CO and two naturally occurring radionuclides, 210Pb and 7Be, showed semiannual cycles similar to those of the pollution-derived trace elements.
Multi‐model analysis of Northern Hemisphere winter blocking: Model biases and the role of resolution

Blocking of the tropospheric jet stream during Northern Hemisphere winter (December‐January‐February) is examined in a multi‐model ensemble of coupled atmosphere‐ocean general circulation models (GCMs) obtained from the Coupled Model Intercomparison Project Phase 5 (CMIP5). The CMIP5 models exhibit large biases in blocking frequency and related biases in tropospheric jet latitude, similar to earlier generations of GCMs. Underestimated blocking at high latitudes, especially over Europe, is common. In general, model biases decrease as model resolution increases. Increased blocking frequency at high latitudes in both the Atlantic and Pacific basins, as well as more realistic variability of Atlantic jet latitude, are associated with increased vertical resolution in the mid‐troposphere to lowermost stratosphere. Finer horizontal resolution is associated with higher blocking frequency at all latitudes in the Atlantic basin but appears to have no systematic impact on blocking near Greenland or in the Pacific basin. Results from the CMIP5 analysis are corroborated by additional controlled experiments using selected GCMs.
Nonlinear climate response to regional brightening of tropical marine stratocumulus

To counteract global warming, there have been suggestions to increase the albedo of low‐level marine clouds through the aerosol indirect effects by injecting them with sea salt. However, the full climate response to this geoengineering scheme is currently poorly understood. We simulate cloud seeding in a coupled mixed‐layer ocean‐atmosphere general circulation model in order to identify the specific physical mechanisms through which seeding could perturb the climate system's radiative balance, and cause temperature and precipitation changes. Seeding stratocumulus decks over three tropical maritime regions in the North Pacific, South Pacific and South Atlantic produces strong local reductions in solar absorption. Over half of the radiative cooling is due to direct scattering of solar radiation by the added sea salt aerosols, while the rest comes from enhancement of the local cloud albedo. The oceanic cooling due to the seeding over the southeastern equatorial Pacific induces a La Niña‐like response, with tropical precipitation changes resembling La Niña anomalies and teleconnections occurring in the mid‐latitude North Pacific and North America. Additionally, model runs in which only one of the three regions is seeded indicate nonlinearity in the climate response. We identify dynamical and thermodynamical constraints respectively on the temperature and hydrological cycle responses to cloud seeding, but the full response to such geoengineering remains poorly constrained.