Miracle-dz/UniFAR-FTUs huggingface dataset:
Chlorinoid and flavinoid pigments from aquatic plants and associated lake and bay sediments

ABSTRACT The content of chlorophyll a of a group of plant species from freshwater, brackish-water and nearshore marine environments was found spectrophotometrically to range from 1 to nearly 300 mg/g on a dry-weight, ash-free basis. The average chlorophyll content of marine, mostly algal, plants from Dillon Beach area, California, was highest among collections studied (38 mg/g), followed by freshwater pondweeds from Minnesota lakes (29 mg/g), marine algae from Coos Bay, Oregon, (25 mg/g) and brackish water pondweeds and algae from Chesapeake Bay (8 mg/g). The low values in Chesapeake Bay species are partly due to the absence of forms that in the other areas studied have chlorophyll values of 100 mg/g or higher. The content of pheophytin a in Minnesota lake sediments from the same, as well as different, localities from which plants were studied amounts to 200-600 ppm of dry organic matter (ash free and corrected for carbonate) in surface samples but only about 70 ppm in silty tidal flat sediments from Tomales Bay, California. In both the marine and freshwater sediments a rapid decrease in pheophytin takes place a few cm beneath the surface. The downward decrease probably results from the utilization of pheophytin as food in the microzone just beneath the surface. The relative pheophytin content of lake sediments although mainly due to the prevailing level of productivity of the lake, is in part governed by the morphometry of the basin and prevailing wind action. Smooth margined, steeply sloping basins show generally not only lower organic productivity but also lower pheophytin content than those with irregular margins and gentle slopes. Some tendency for sedimentary pheophytin enrichment was noted on the lee sides of the latter type of lake due to wave transport. A period of relatively high organic productivity between depths of 500 and 700 cm in sediments of Blue Lake, Minnesota is reflected in an increase in chlorinoid pigments at these depths. A variety of fluorescent substances tentatively identified as flavinoids, indole acids and other heterocyclic substances have been found in lake and bog deposits and associated plants. These are believed to have been formed by organisms living in the sediments. In a general way the fluorescent substances represent the products of animal metabolism under poorly oxidative conditions, and the amount reflects the level of such activity in individual deposits. An episode of increased sedimentary-biologic activity of depths of 8 to 10 meters (dark copropel layer) in Cedar Creek Bog, Minnesota is suggested by an increase in flavinoid pigments in sediments at these depths.
Efficacy of Hydroxyapatite Nanoparticles as Phosphorus Fertilizer in Andisols and Oxisols

Improving phosphorus (P) fertilizer efficiency is a challenge in acidic and strongly P sorbing soils. Nanotechnology may have potential to create more efficient fertilizers. Hydroxyapatite nanoparticles (n-HAP) were evaluated as a potential fertilizer to improve P efficiency based on the hypothesis that nano-sized particles can potentially move in the soil and reach the plant roots through the mass flow of soil water to roots created by transpiration. The transport of nano-sized and bulk-sized HAP was evaluated in saturated soil column experiments. Availability of P from n-HAP, bulk-HAP, and triple superphosphate (TSP) to wheat (Triticum aestivum) was evaluated by a ³³P isotopic dilution technique in a glasshouse study with two Andisols from Chile and New Zealand and two Oxisols from Australia. Transport experiment showed that 5% of the applied n-HAP leached in the Andisol and n-HAP > bulk-HAP. Although n-HAP performed better than bulk-HAP, most likely because of faster dissolution, TSP was still a more efficient P fertilizer.
Isotopic signatures of sulfur in shallow Antarctic ice cores

Sulfur stable isotopes from Antarctic snow samples have been used to assess sources of sulfate. The novel experimental procedure presented here is suitable for the determination of sulfur isotopic composition at the micromolar level and has been adapted to polar ice samples. Measurements were carried out on three contiguous firn cores (PS6, PS7, and PS8) collected near Amundsen-Scott Station (South Pole), covering the record of the Agung eruption (March 1963). Taking into account the minimum amount of sulfate required for the isotope analysis, it has been possible to delineate three time periods along the cores: pre-1964 years (background sulfate level), 1964–1965 (volcanic deposition peak), and 1966–1968 (volcanic peak tail). A deeper part of another core (PS12) has been used to extend the background picture. Assuming the conservation of isotopic signatures during long-range transport and deposition processes, results demonstrate the significant volcanic contribution to sulfate deposition on the central Antarctic ice cap a few months after a major low-latitude eruption. They also confirm the marine biogenic origin of present background sulfate. Isotopic signatures (δ34S) of marine biogenic sulfate and volcanic sulfate from Mt. Agung have been found to be +18.6±0.9‰ and +2.7± . 1‰, respectively.
Estimating soil moisture using Temperature–Vegetation Dryness Index (TVDI) in the Huang-huai-hai (HHH) plain

Soil moisture is an important indicator to describe soil conditions, and can also provide information on crop water stress and yield estimation. The combination of vegetation index (VI) and land surface temperature (LST) can provide useful information on estimation soil moisture status at regional scale. In this paper, the Huang-huai-hai (HHH) plain, an important food production area in China was selected as the study area. The potential of Temperature–Vegetation Dryness Index (TVDI) from Moderate Resolution Imaging Spectroradiometer (MODIS) data in assessing soil moisture was investigated in this region. The 16-day composite MODIS Vegetation Index product (MOD13A2) and 8-day composite MODIS temperature product (MOD11A2) were used to calculate the TVDI. Correlation and regression analysis was carried out to relate the TVDI against in-situ soil moisture measurements data during the main growth stages of winter wheat/summer maize. The results show that a significantly negative relationship exists between the TVDI and in-situ measurements at different soil depths, but the relationship at 10–20 cm depth (R 2 = 0.43) is the closest. The spatial and temporal patterns in the TVDI were also analysed. The temporal evolution of the retrieved soil moisture was consistent with crop phenological development, and the spatial distribution of retrieved soil moisture accorded with the distribution of precipitation during the whole crop growing seasons. The TVDI index was shown to be feasible for monitoring the surface soil moisture dynamically during the crop growing seasons in the HHH plain.
Factors Influencing the Formation and Characteristics of Halloysites or Kaolinites in Granitic and Tuffaceous Saprolites in Hong Kong

The occurrence of halloysite and/or kaolinite in clay-rich, vein-like zones in saprolites in Hong Kong has provided the opportunity to examine the conditions determining the formation of one kaolin mineral or the other and also the nature of their particles. Clay-rich zones within tuffaceous or granitic saprolites from six different hillside sites have been examined in replicate samples by optical and scanning electron microscopy, X-ray diffraction, and thermal analysis. Kaolin minerals, sometimes together with Mn oxides and Fe oxides/oxyhydroxides, have formed within discontinuities within the altered host rocks. The fabrics of kaolin infills generally indicated several generations of kaolin formation and that shear and deformation have commonly occurred within the infills. The infills were either light or dark in color. Light-colored infills often comprised pure, or nearly pure, halloysite or kaolinite. Dark Mn- and Fe-rich infills all contained kaolinite, while including some halloysite. The very halloysitic, light-colored infills occurred in saprolites in both granite and tuff as long tubular shapes in parallel bunches. The light-colored, very kaolinitic infills occurred in tuff only, in large platy or near-platy shapes within vermiform packets. In dark-colored infills, early kaolin mineral crystallization was limited by impurities from the breakdown of primary minerals leaving dissolved and re-precipitated compounds of Mn and Fe within the infill. Kaolin minerals in infill at all the sites except one are considered to have formed as a result of weathering. The exception comprises white infills in tuff that are composed of extremely small, closely packed particles, suggesting formation by hydrothermal action. Generally, the kaolin minerals have formed by neogenesis out of solution in the discontinuities. Drying, with the formation of Mn and/or Fe oxides/oxyhydroxides, had occurred several times, indicating enhanced drainage. Where drying had occurred, kaolinite had formed. Where indications of drying in infills were absent, halloysite was predominant.
Seismic liquefaction, lateral spreading, and flow slides: a numerical investigation into void redistribution

Experience from past earthquakes indicates that seismically induced large lateral spreads and flow slides in alluvial sand deposits have taken place in coastal and river areas in many parts of the world. The ground slope in these slides was often not very steep, gentler than a few percent. Recent research indicates that the presence of low-permeability silt or clay sublayers within the sand deposits is responsible for this behaviour. Such layers form a barrier to upward flow of water associated with earthquake-generated pore pressures. This causes an accumulation of pore water at the base of the layers, resulting in greatly reduced strength and possible slope instability. This paper uses an effective stress coupled stress-flow dynamic analyses procedure to demonstrate the effects of a low-permeability barrier layer on ground deformations from an earthquake event. The analyses show that an expansion zone develops at the base of barrier layers in stratified soil deposits under seismic loading which can grea.
Review of Miocene shallow marine and lacustrine depositional environments in Northern Croatia

The Neogene and Quaternary depositional and structural characteristics of the southwestern Croatian Pannonian Basin System (CPBS) are unique within the Pannonian Basin System (PBS). Due to its position at the basin margin, the area was covered by shallow and partially isolated parts of the Pannonian Sea in the Badenian (Mid Miocene). Later, in the Pannonian and Pontian ages, the area contained several brackish lakes, the largest being Sava Lake and Drava Lake. Tectonic events, sedimentation and depositional mechanisms occurring during the Neogene in the CPBS have revealed that those areas can be considered as former shallow seas or lakes dominated by clastic sedimentation. Marine coarse-grained clastic sedimentation took place during the Badenian, with local sources of material and numerous alluvial fans developed during the first transtensional phase. In the Pannonian and Pontian (Late Miocene), sediments were deposited by turbidity currents from a single, distal material source located in the Eastern Alps during the second transtensional tectonic phase.
First report of protoceratopsians (Neoceratopsia) from the Late Cretaceous Judith River Group, Alberta, Canada

Protoceratopsians are best known in North America from associated skeletal material of Montanoceratops from the early Maastrichtian of Montana and Campanian of Alberta and Leptoceratops from the late Maastrichtian of Alberta and Wyoming. We report here the first occurrence of protoceratopsian elements from the middle Campanian (Dinosaur Park Formation) of Alberta. The specimens consist of a fragmentary right dentary and an almost complete left dentary which can be referred to Leptoceratops sp. Recent examination of Albertan microvertebrate material has identified cf. protoceratopsians teeth from the latest Santonian (Milk River Formation), extending the record of Albertan protoceratopsians back almost 20 million years. The rarity of these small ornithischians in the fossil record of Alberta may have been due to ecological exclusion from the wet, coastal environments that were preferred by the larger, more abundant ceratopsids.
The Effect of Water Chemistry on the Laboratory Compression and Permeability Characteristics of Some North Sea Chalks

Chalks or chalk-like carbonates have been reported to fail when returned to or near in-situ reservoir stress in the laboratory. Failure of chalks during reservoir production tests has also been reported. This paper presents laboratory results showing that the compaction behavior of the chalks is dependent on the water chemistry of the saturating fluid. The chalks were found to be strong and stable under hydrostatic stress when saturated with oil. Injection of water into the oil saturated chalks, at stress, caused immediate compaction. The weakening of chalks by water increased the compressibility values four to eight times the oil saturated values. The chalks resisted failure when stabilized with synthesized formation water containing calcium/bicarbonate ratios equal to the calcium/bicarbonate ratio present in the formation-water analysis. Permeabilities of the chalks saturated with oil and brines are also presented.
Systematics and phylogenetic implications of the haplosclerid stromatoporoid Newellia mira nov. gen.

Wood, Rachel, Reitner, Joachim & West, Ronald R. 1989 01 15: Systematics and phylogenetic implications of the haploslerid stromatoporoid Newellia mira nov. gen. Lethaia, Vol. 22, pp. 85–93. Oslo. ISSN 0024–1164. The presence of spicules in a Palaeozoic stromatoporoid is here confirmed. Parallelopora mira Newell, 1935 from the Upper Carboniferous of the U.S.A. is redescribed as a calcified haplosclerid sponge with a primary siliceous spicule framework of isodictyally arranged styles, sub-tylostyles and strongyles and a secondary calcareous skeleton of stromatoporoid grade and probable aragonitic original mineralogy. P. mira is placed within a new genus Newellia, and family, the Newellidae. This form is postulated to have possessed large amounts of collagenous organic material which enveloped and bound the spicular framework in place. By the draping outline of the calcareous skeleton around the spicule framework and by analogy with the Recent demosponge genus Vaceletia, the calcareous skeleton is suggested to have formed by the direct mineralization of this collagenous template. Newellia mira nov. gen. is further proposed to constitute a member of a new clack of haplosclerid stromatoporoids, together with Euz-Miella erenoensis (Lower Cretaceous); a clade with some similarity to Recent non-calcified forms, e.g. Adocia. Most notably, the presence of different calcareous skeleton mineralogies and possibly microstructures in these two forms suggests the independent development of a calcareous skeleton at different times within this spicule clade. Demosponges appear to have produced calcareous skeletons independently in many different spicule clades. Calcified demosponges are now known from the Hadro-merida (Lower carboniferous; Upper Cretaceous - Recent), Axinellida (Upper Triassic - Lower Cretaceous; Upper Cretaceous; Recent), Poecilosclerida (Recent) as well as the Haplosclerida (Upper Carboniferous - Lower Cretaceous; Recent). □Upper Carboniferous, stromatoporoid, spicules, haplosclerid demosponges, calcareous skeleton biomineralization, demosponge clades, polyphyly.
Seafloor evidence for the interaction between cascading and along-slope bottom water masses

[1] The steep slope of the SW Adriatic margin (Central Mediterranean) is impacted today by two water masses having markedly different origin but a similar southward flow component: the Levantine Intermediate Water (LIW) and the North Adriatic Deep Water (NAdDW). The LIW forms through evaporation in the eastern Mediterranean and enters the Adriatic along a counterclockwise path. The NAdDW forms through winter cooling on the North Adriatic shelf and cascades across the western slope of the South Adriatic basin. Bathymetric and side-scan sonar (TOBI) images of the SW Adriatic margin, accompanied by Chirp sonar profiles, define an area of extreme seafloor complexity characterized by a variety of sediment waves, erosional scours, longitudinal furrows, and giant comet marks. These distinctive bottom-current features are not randomly distributed but appear genetically linked and have a consistent down-current arrangement. We ascribe this seafloor pattern to the constructive interference of the highly saline LIW, flowing along the slope between 200- and 600-m water depth, and the cold NAdDW, plunging off-shelf obliquely to the slope. Stratigraphic data indicate that this oceanographic regime has been active since the last glacial-interglacial transition. The cascading NAdDW is density driven but is not short-lived (as a turbidity current would be); consequently, the interaction between downslope and along-slope currents is here more dynamical as two water masses act simultaneously over a prolonged interval, somewhat diverting their paths and leading to locally enhanced energetic conditions at the seafloor.
Gravity wave interactions around the jet stream

VHF radar measurements have been applied to study the interaction between a mountain wave and an inertia‐gravity wave above the jet stream in the tropopause region. The mountain wave was observed to break and generate turbulence at a critical level that was induced by the inertia‐gravity wave. This indicates that wave‐wave interactions can be an important source of turbulence and, consequently, mixing in the tropopause region.
Sonic velocity and grain contact properties in reservoir sandstones

The purpose of this study was to examine the effect of grain contacts and quartz cementation with regard to acoustic wave propagation in sandstones. Grain contacts have been considered essential when relating acoustic velocities to physical rock properties, and a parameter numerically representing the contact area between individual grains (contact length) has been measured. The method used involves digital petrographic microscopy pictures analysed by image analysis software. Other parameters, such as grain size, number of grain-to-grain contacts, cracks, clay content and porosity, have also been closely examined. The results showed that the contact area between sand grains may be useful for explaining velocity variations during the initial stages of quartz cementation and grain framework stiffening. Continued increase in grain-contact area by chemical compaction will have less influence on the sonic velocity compared to variations in porosity. The Garn Fm. from the Norne Field (2.6–2.7 km burial depth), which is in the early phase of initial grain framework stiffening by quartz cementation, and the Garn Fm. from the Kristin Field (4.6–4.7 km burial depth), which is thoroughly quartz cemented, were chosen as sample materials. Log-derived velocities, in addition to some laboratory ultrasonic velocity measurements, were used in this study.
Mechanisms of deformation localization at the tips of shear fractures: Findings from analogue experiments and field evidence

[1] Using analogue experiments on polymethylmethaacrylate (PMMA) models, we investigated the process of deformation localization at the tips of preexisting planar shear cracks. Experiments show that this can take place in any of the following four principal mechanisms. Mechanism A: Brittle deformation is the dominant process and forms a pair of long tensile fractures at the crack tips. The tensile fractures propagate along the compression direction and transgress the entire model thickness, causing model failure at a small bulk strain (3%). Mechanism B: It involves both brittle and ductile (plastic) strain localization, where the tensile fractures grow to a limited length and incipient ductile zones appear at the tips. Mechanism C: Deformation localization is characterized by an association of macroscale shear bands and short, opened-out tensile fissures (cf. wingfractures). Mechanism D: Ductile strain localizes in the form of a pair of shear bands at each tip. Fracture failure does not occur in this case. The transition from Mechanism A to Mechanism D is a continuous phenomenon in the experimental conditions, which we show as a function of initial crack angle (α angle between the crack and the far-field compression direction) and crack length (l). Mechanism A tends to be replaced by Mechanism D with decreasing α (60° to 20°) and/or l. Using a finite element method (FEM), we calculated the maximum principal tensile stress (σ1max) and the maximum second stress invariant (I2max) of the stress field in the neighborhood of a sliding crack within a linearly elastic medium and analyzed the brittle-ductile transitions observed in physical experiments. The calculations show that σ1max is directly proportional to l and attains a peak value for α = 45°, promoting Mechanism A. On the other hand, I2max occurs at α 45° in physical models with simultaneously varying crack length and orientation. We also demonstrate probable interactions between plastic strain localization and tensile fracturing at the crack tips. FEM results indicate that a plastic zone lowers the magnitude of tensile stress concentration at wing cracks and thereby dampen their growth when α < 45°. We finally complement our study with field examples.
Vertical moisture profile characteristics of severe surface drought and surface wetness in the western United States: 1973–2002

Drought can be viewed as a three‐dimensional phenomenon rather than simply a surface feature. We characterize drought across the western United States from 1973 to 2002 in a three‐dimensional context by examining its vertical moisture extent using NCEP/NCAR Reanalysis data derived from rawinsonde moisture profiles. We then apply a discriminant analysis to establish the degree of difference between the vertical moisture profiles of extreme drought and extreme wetness conditions. The mean vertical moisture profiles of dry cases are measurably drier than those of wet regions, particularly at the lower levels of the profile. The discriminant analysis of the 9254 cases indicates that moisture in the lowest (850 hPa) level of the profile is most important in identifying dry versus wet regions, and, consequently, implies a strong influence of convective precipitation in defining surface drought and wet conditions in the study region. Copyright © 2009 Royal Meteorological Society
Satellite observations of upper stratospheric and mesospheric OH: The HOxdilemma

We report the first observations of the vertical distribution of hydroxyl (OH) from the upper stratosphere to the mesopause. The Middle Atmosphere High Resolution Spectrograph Investigation (MAHRSI) made these measurements in August 1997. The data confirm the results from the earlier November 1994 MAHRSI mission that were confined to altitudes above 50 km, namely that mesospheric OH densities are 25 to 35% lower than predicted by standard photochemical theory. However, the new observations show that below 50 km the OH density increases rapidly and at 43 km altitude it is larger than that expected from standard theory. This represents a serious dilemma for our understanding of odd‐hydrogen chemistry because the same key reactions are thought to dominate OH/HO2 partitioning in both regions. We show that neither standard photochemical theory nor any previously proposed changes are adequate to explain the OH observations in both the upper stratosphere and mesosphere.