Miracle-dz/UniFAR-FTUs huggingface dataset:
Assessing the performance of multi-frequency GPS, Galileo and BeiDou PPP ambiguity resolution

ABSTRACT The authors investigate the benefits for the precise point positioning (PPP) ambiguity resolution technique of using the GPS L1, L2 and L5; Galileo E1, E5a, E5b and E6; and BeiDou B1, B2 and B3 measurements. Data from 17 reference stations over a period of 31 consecutive days in 2018 were used. It was found that the four-frequency Galileo combination of E1+E5a+E5b+E6 provides the lowest geometric and ambiguity variance. In a kinematic test using triple- and four-frequency GNSS measurements, the solution convergence time can be shortened by an average of 5 minutes as compared to the triple-frequency GPS-only PPP case.
Measuring Sperm whales via Acoustics and Photogrammetry

The most common vocalisations heard from sperm whales are short, broadband clicks which often display a decaying, evenly spaced, multi-pulse structure. The time between these pulses (inter-pulse interval: IPI) represents the two-way time for a pulse to travel between the air sacs located at either end of the sperm whale‟s head. The IPI therefore, is measure of head length and via an allometric relationship, total length. In order to compare IPIs of known individuals to an independent measure of length, a new, boat-based fully digital stereo photogrammetric system was developed and its measurement accuracy assessed. A field test was conducted measuring objects of known length throughout a distance/angle network. Mean measurement error over the entire network was 0.82% and it was found that the largest contributor to measurement error was the repeated manual selection of conjugate points in stereo images. IPIs were measured using a newly developed software plugin 1 for Pamguard, an open-source software package for passive acoustic monitoring. The plug-in was based on the recently developed “bent horn” theory of sound production in sperm whales. Previous studies relating IPI to an independent measure of length have suffered from very small sample sizes. Therefore, this study measured 21 sperm whales off Kaikoura, New Zealand using the new photogrammetric and acoustic method. Both measurement methods produced results which were repeatable and more accurate than previously published studies (mean C.V = 1.57% and 0.63%, respectively). A new equation describing the relationship between IPI and total length was proposed. To further boost sample size, the IPI plugin was also used to measure IPIs from archived recordings of whales that had been measured with a previous photogrammetric system. This brought the total sample size of different whales with both IPI measurements and stereo photogrammetric measurements to 33. Finally the IPI plugin was used to estimate acoustically the growth rates of 29 seasonal resident sperm whales which had been repeatedly recorded between 1991 and 2009. Most whales showed an increase in IPI over time representing growth. For individuals that were recorded many times over several years von Bertalanffy growth curves fitted the data well (mean r 2 = 0.83; range = 0.130.99). This is the first time growth has been estimated using an acoustic method and because it is non-lethal it has the potential to allow different types of questions related to growth to be investigated. 1 Developed by Miller (2010).
Melting of Al‐Rich Phase D up to the Uppermost Lower Mantle and Transportation of H2O to the Deep Earth

We investigated the stability of the Al‐rich dense hydrous magnesium silicate Phase D (PhD) in a MgO‐Al2O3‐SiO2‐H2O system between 14 and 25 GPa at 900–1,500 °C. Al‐rich PhD has a very wide stability region from 900 °C and 14 GPa to at least 1,500 °C and 25 GPa, showing strong temperature stability with increasing pressure. Al‐rich PhD decomposes to Phase Egg at pressure of the mantle transition zone, whereas it decomposes to δ‐AlOOH phase with a temperature increase at pressure of the uppermost lower mantle. X‐ray diffraction and Raman spectroscopy measurements of Al‐rich PhD show that the unit‐cell volume is slightly larger, but the Raman spectra resemble that of Al‐free PhD. The wide stability region of Al‐bearing PhD would contribute an important storage site for water in the mantle transition zone, suggesting that it can deliver a certain amount of water into the lower mantle along hot subduction and even at the normal mantle geothermal P‐T condition. Furthermore, the dehydration of Al‐bearing PhD might be responsible for a series of observed seismic discontinuities from the transition zone to the uppermost lower mantle and even for deep earthquakes in some typical locations.
The Dependence of Shallow Cumulus Macrophysical Properties on Large‐Scale Meteorology as Observed in ASTER Imagery

This study identifies meteorological variables that control the macrophysical properties of shallow cumulus cloud fields over the tropical ocean. We use 1,158 high‐resolution Advanced Spaceborn Thermal Emission and Reflection Radiometer (ASTER) images to derive properties of shallow cumuli, such as their size distribution, cloud top heights, fractal dimensions, and spatial organization, as well as cloud amount. The large‐scale meteorology is characterized by the lower‐tropospheric stability, subsidence rate, sea surface temperature, total column water vapor, wind speed, wind shear, and Bowen ratio. The surface wind speed emerges as the most powerful control factor. With increasing wind speed the cloud amount and cloud top heights show a robust increase accompanied by a marked shift in the cloud size distribution toward larger clouds with smoother shapes. These results lend observational support to the deepening response of a wind‐driven marine boundary layer as simulated by large‐eddy models. The other control factors cause smaller changes in the cloud field properties. We find a robust increase in cloud amount with increasing stability and decreasing sea surface temperature, respectively, which confirms a well‐known behavior of marine stratocumulus also for shallow cumulus clouds. Due to the high resolution of cloud images, we are able to study the lower end of the cloud size distribution and find a robust double power law behavior with a scale break at 590 m. We find a variation in the shape of the cloud size distribution with Bowen ratio, qualitatively consistent with modeling results and suggesting the Bowen ratio as a new potential control factor on shallow cumulus clouds.
Changes in subsoil acidity with a new deep vertical lime placement practice for conservation tillage systems

Poorly drained claypan soils in the midwestern United States that are managed for corn (Zea mays L.) and soybean (Glycine max [L.] Merr.) production often have optimum surface pH for crop growth, but are characterized by acidic subsoils. Stratification of soil acidity may inhibit root growth leading to decreased drought tolerance and grain yields. Agricultural lime application can increase soil pH and provide calcium (Ca) to the soil, but these amendments rarely affect the subsoil, especially when a conservation tillage system that results in minimal lime incorporation is utilized. The objectives of this study were to determine the effects of surface lime placement compared to a novel deep vertical lime placement practice at various rates on subsoil characteristics under corn and soybean production. Field trials were conducted from 2012 to 2016 in northeast Missouri with treatments of aglime broadcast to the surface soil or incorporated as a vertical band using a custom built shank to a depth of 51 cm (20 in) into the subsoil at 0, 3.4, and 6.7 Mg lime ha−1 (0, 1.5, and 3.0 tn lime ac−1). Soil pH results indicated that the top 13 cm (5 in) of soil was not affected by deep lime placement, but at depths of 13 to 25 cm (5 to 10 in) soil pH increased up to 0.6 and 0.7 units for deep vertical placed lime at 3.4 and 6.7 Mg ha−1, respectively. When compared with control treatments, vertical placement of lime at 3.4 and 6.7 Mg ha−1 increased subsoil pH at depths of 13 to 25 and 25 to 38 cm (10 to 15 in), respectively, one year after application. A similar comparison with the control treatment indicated that deep vertical placement at 6.7 Mg ha−1 increased subsoil pH at 13 to 25 cm depths by 6.5% and 5.7% two and three years after application, respectively. Analysis of the spatial distribution of soil pH and neutralizable acidity in the soil profile indicate penetration of liming effects up to 38 cm (15 in) into the subsoil, but there was minimal evidence of movement away from the initial vertical placement band during a seven-month period.
Spatial variation of groundwater response to multiple drivers in a depleting alluvial aquifer system, northwestern India

Unsustainable exploitation of groundwater in northwestern India has led to extreme but spatially variable depletion of the alluvial aquifer system in the region. Mitigation and management of groundwater resources require an understanding of the drivers behind the pattern and magnitude of groundwater depletion, but a regional perspective on these drivers has been lacking. The objectives of this study are to (1) understand the extent to which the observed pattern of groundwater level change can be explained by the drivers of precipitation, potential evapotranspiration, abstraction, and canal irrigation, and (2) understand how the impacts of these drivers may vary depending on the underlying geological heterogeneity of the system. We used a transfer function-noise (TFN) time series approach to quantify the effect of the various driver components in the period 1974–2010, based on predefined impulse response functions (θ). The dynamic response to abstraction, summarized by the zeroth moment of the response M0, is spatially variable but is generally large across the proximal and middle parts of the study area, particularly where abstraction is high but alluvial aquifer bodies are less abundant. In contrast, the precipitation response is rapid and fairly uniform across the study area. At larger distances from the Himalayan front, observed groundwater level rise can be explained predominantly by canal irrigation. We conclude that the geological heterogeneity of the aquifer system, which is imposed by the geomorphic setting, affects the response of the aquifer system to the imposed drivers. This heterogeneity thus provides a useful framework that can guide mitigation efforts; for example, efforts to decrease abstraction rates should be focused on areas with thinner and less abundant aquifer bodies.
Thermal Transport Properties of Olivine, Wadsleyite, and Ringwoodite—A Review

Knowledge of the thermal diffusivity D and thermal conductivity κ of olivine and its high-pressure polymorphs, wadsleyite and ringwoodite, is crucial to understand the heat transfer efficiency and thermal structure of Earth’s mantle. In the last few decades, great progress has been made in measurement techniques and experimental results seeking to determine the thermophysical properties of geomaterials. The aim of this paper is to provide a systematic overview of the current knowledge of the thermal transport properties of olivine and its high-pressure polymorphs, their dependence on factors, such as pressure, temperature, and composition, and physical models to describe their variations. Some related geoscience applications and perspectives for the future are also suggested.
The Role of Protein Kinase C in the Extracellular Ca2+-regulated Secretion of Parathyroid Hormone

The sensing of extracellular Ca(2+) concentration ([Ca(2+)](o)) and modulation of cellular processes associated with acute or sustained changes in [Ca(2+)](o) are cell-type specific and mediated by the calcium sensing receptor (CaR). [Ca(2+)](o) signalling requires protein kinase C (PKC), but the identity and role of PKC isoforms in CaR-mediated responses remain unclear. Here we show that high [Ca(2+)](o) activated PKC-alpha and PKC- in parathyroid cells and in human embryonic kidney (HEK293) cells overexpressing the CaR (HEK-CaR) and that this response correlated with the CaR-dependent activation of mitogen-activated protein kinases ERK1/2. Activation of ERK1/2 by acute high [Ca(2+)](o) required influx of Ca(2+)through Ni(2+)-sensitive Ca(2+)channels and phosphatidylinositol-dependent phospholipase C-beta activity. Inhibition of PKC by co-expression of dominant-negative (DN) mutants of PKC-alpha or - with the CaR attenuated sustained ERK1/2 activation. Overexpression of a PKC phosphorylation site (T888A) mutant CaR in HEK293 cells showed that this site was important for ERK1/2 activation at high [Ca(2+)](o). Activation of ERK1/2 by high [Ca(2+)](o) was not necessary for the [Ca(2+)](o)-regulated secretion of parathyroid hormone (PTH) in dispersed bovine parathyroid cells. These data suggest that the CaR-mediated [Ca(2+)](o) signal leading to regulated PTH secretion that requires diacylglycerol-responsive PKC isoforms is not mediated via the ERK pathway.
The Impact of Tree Species, Elevated Nitrogen Deposition, Stand Age, and Environmental Factors on Herbaceous Plant Communities in a Central Appalachian Hardwood Forest

The Impact of Tree Species, Elevated Nitrogen Deposition, Stand Age, and Environmental Factors on Herbaceous Plant Communities in a Central Appalachian Hardwood Forest Lacey J. Smith Although the herb layer represents less than 1% of the biomass of temperate forests, this layer may contain up to 90% of the plant species in the forest and can contribute up to 20% of the foliar litter, thus playing an essential role in forest biodiversity and nutrient cycling. The objectives of this study were to investigate the differences in cover, species richness, ShannonWiener diversity, and evenness of herb layer plants a) under tree species associated with contrasting soil nitrogen levels and b) in watersheds that vary in nitrogen deposition, stand age, and watershed aspect at the Fernow Experimental Forest in West Virginia. In the watersheds evaluated, overstory tree species, N deposition level, stand age, and other environmental factors influenced herb layer characteristics. This study demonstrated 1) a sugar maple effect, i.e. sugar maple having a positive effect on understory cover, at intermediate levels of soil fertility in reference watersheds and in an N-fertilized watershed by improving the nutrient microenvironment for herb layer plants, 2) that long-term N enrichment can reduce ecosystem biodiversity by favoring nitrophilic species, and 3) that herb layer characteristics can be influenced by stand age, with more recent disturbance being reflected in higher herb layer abundance and diversity. This study justifies further examination of tree-herb layer interactions for a wider range of tree species, N-deposition levels, and stand ages in future studies in order to inform adaptive forest management in the light of climate change and other continuing anthropogenic influences.
The Carbon Balance of the Southeastern U.S. Forest Sector as Driven by Recent Disturbance Trends

This study documents annual carbon stocks and fluxes from 1986 to 2010 at 30‐m resolution across southeastern U.S. forests, analyzing trends and regional greenhouse gas exchange. We used forest inventory data to guide a carbon cycle model representing postdisturbance carbon dynamics for diverse forest and site conditions. We mapped carbon stocks and fluxes with stand age inferred from spaceborne disturbance monitoring and biomass. We assessed the fate of harvested biomass with a wood products model. We found that pine forests experienced the largest biomass removals, with paper products leading all end‐uses. Averaging across all SE forestlands, mean annual net ecosystem productivity decreased from 116 gC · m−2 · year−1 in 1986 to 71 gC · m−2 · year−1 in 2007, and 85 gC · m−2 · year−1 in 2010, equating to a range of 25 to 41 Tg C/year (mean of 34 Tg C/year). Interannual variability in forest‐atmosphere carbon exchange is dominated by the extent of harvesting, with removals ranging from 23 to 56 Tg C/year. Region‐wide live biomass stocks varied little over time, averaging 5.0 kg C/m2 for aboveground biomass or 1,780 TgC, with average annual biomass growth balanced by harvest removals. However, net biome productivity exhibited large interannual variability, spanning a sink of 16 Tg C/year in 1986 to a source of −30 Tg C/year in the year of peak harvest. Two thirds of harvest removals are emitted within 50 years, 8% as methane, causing the forest sector to act as a large CO2‐equivalent source. Uncertainties are estimated at ± 25%.
Different responses of chlorophyll-a concentration and Sea Surface Temperature (SST) on southeasterly wind blowing in the Sunda Strait

During southeast monsoon, along the western coast of Sumatra Island and southern coast of Java Island are known as the coastal upwelling areas denoted by the occurrence of Sea Surface Temperature (SST) cooling and chlorophyll-a blooming. Located between Sumatra and Java Islands, Sunda Strait waters may give different response to the southeasterly wind blowing above. Using SST and chlorophyll-a data obtained from daily MODIS level 3 during 2006–2016, this study demonstrated the evidence on how bathymetry and topography modified the effect of southeasterly wind on the spatial variability of SST and chlorophyll-a. All datasets were composed into monthly and monthly climatology. The area in the center of Sunda Strait had the lowest chlorophyll-a concentration and the warmest SST during the peak of upwelling season. The deep bottom topography and the absence of barrier land prevented the generation of wind driven coastal upwelling. However, the chlorophyll-a concentration in this area had the highest correlation with the wind speed which means that the variation of chlorophyll-a concentration in this area was highly depended on the variability of wind. On the other hand, the areas with shallow bathymetry and in front of Panaitan and Java Islands had higher chlorophyll-a concentration and cooler SSTs.
Organic Aerosol Processing During Winter Severe Haze Episodes in Beijing

Organic aerosol (OA) constituted a large fraction of aerosol particles during severe haze episodes in winter in northern China, yet our understanding of its physical and chemical processing was limited. Here we investigate the sources and processes of OA during four haze episodes in winter in 2016 using high‐resolution aerosol mass spectrometer. The PM2.5 reached 400 μg/m3 during the severest episode (Ep1) when Beijing issued a red alert and implemented strict emission controls. Our results showed that secondary OA (SOA) dominated OA during haze episodes on average accounting for 46–66% of OA and was comparable to secondary inorganic aerosol (SIA) with the SOA/SIA ratios being 0.51–0.72. Primary OA from fossil‐fuel combustion, biomass burning, and cooking presented very strong diurnal variations during haze episodes and contributed up to 60% in OA at night. Comparatively, the changes in semivolatile and low‐volatility SOA were relatively small except a substantial increase in aqueous phase‐related oxidized OA (aq‐OOA) during Ep1 with high relative humidity and aerosol water content. aq‐OOA fell well into a small region in the middle of the triangle plot of f44 versus f43 (fraction of m/z 44 and 43 in OA, respectively), which can be used as a diagnostic for the presence of aqueous phase processing of SOA. In addition, the increases of SO2+/SO3+ as a function of relative humidity, the triangle plot of fH2SO4+ versus fHSO3+ , and high nitrogen‐to‐carbon ratio in aq‐OOA suggest the potential formation of sulfur‐ and nitrogen‐containing organic compounds through aqueous phase processing.
Pollen Morphology of Tribes Alsineae and Sperguleae (Caryophyllaceae) and Its Systematic Significance

ABSTRACT Pollen morphology of 79 species, one subspecies and eight varieties representing nine genera of tribe Alsineae and two of tribe Sperguleae was studied using light microscopy (LM) and scanning electron microscopy (SEM). Among them, 53 species and eight varieties (22 species of which are endemic to China) were reported for the first time. The results demonstrate that the number of pores, the pollen surface ornamentation and the density of microechini have important systematic significance. The surface ornamentation can be divided into three types, namely microechinate-perforate, microechinate-punctate, and microechinate-punctate-perforate. Pollen characteristics support: (i) isolation of Arenaria subgenus Odontostemma from Arenaria and reclassification of Arenaria subgenus Odontostemma to Odontostemma; (ii) isolation of Cerastium subgenus Dichodon from Cerastium and reclassification of Cerastium subgenus Dichodon to Dichodon; (iii) isolation of Minuartia subgenus Rhodalsine from Minuartia and reclassification of Minuartia subgenus Rhodalsine to Rhodalsine; (iv) isolation of Rhodalsine from tribe Alsineae and reclassification of Rhodalsine into tribe Sperguleae; and (v) isolation of Sagina from tribe Alsineae. In addition, the relationships of Arenaria subgenus Eremogone and Arenaria subgenus Eremogoneastrum to tribe Alsineae need to be further studied. Furthermore, pollen characteristics indicate that tribe Alsineae is more evolved than tribe Sperguleae.
Vegetation type and plant diversity affected soil carbon accumulation in a postmining area in Shanxi Province, China

Coal mining causes severe land degradation, which poses a great damage to carbon (C) sequestration function of the original ecosystem. Vegetation restoration in postmining areas plays an important role in rebuilding soil C pool and improving soil quality. In this study, soil C sequestration and soil properties of different vegetation types were investigated along restoration chronosequences in a postmining area in the eastern Loess Plateau. The results showed that soil properties improved substantially through artificial restoration by planting Rhus typhina (exotic species) and Platycladus orientalis (indigenous species) and through natural restoration. Soil C stock (0–20 cm depth) increased significantly with restoration duration in all of the vegetation types and was positively correlated to plant diversity except in R. typhina. After 12–20 years from restoration, accumulation rates of soil C varied significantly with vegetation type, with the maximum in P. orientalis (0.60 Mg ha−1 yr−1) and the minimum in naturally restored grassland (0.21 Mg ha−1 year−1). The optimum performance of P. orientalis plantation could be attributed mainly to high plant diversity and associated high fine root biomass (1.72 Mg ha−1). A sharp decrease of plant diversity (39.0%) in R. typhina 12 years after restoration implied that soil C accumulation might not be sustainable in the long term. Our results suggest that P. orientalis as an indigenous species adaptable to harsh environment may facilitate the succession of a diverse ecosystem and promote soil C accumulation in degraded lands of postmining areas.