Miracle-dz/UniFAR-FTUs huggingface dataset:
Punctuated eustatic sea-level rise in the early mid-Holocene

Whether eustatic sea-level rise through the Holocene has been punctuated or continuous has remained controversial for almost two decades. Resolving this debate has implications for predicting future responses of remaining ice sheets to climate change and also for understanding the drivers of human settlement and dispersal patterns through prehistory. Here we present a sea-level curve for the past 8900 yr from Singapore, a tectonically stable location remote from ice-loading effects. We also present critical and unique sedimentation rate, organic δ13C, and foraminiferal δ13C proxy records of sea-level change derived from a shallow-marine sediment core from the same area over the same time interval. The sea-level curve, corroborated by the independent proxy records, suggests rapid rise at a rate of 1.8 m/100 yr until 8100 cal (calibrated) yr B.P., a near cessation in the rate of sea-level rise between 7800 and 7400 cal yr B.P., followed by a renewed rise of 4–5 m that was complete by 6500 cal yr B.P. We suggest that this period of relatively stable sea level during the early to mid-Holocene enabled modern deltas to advance, providing a highly productive environment for the establishment of coastal sedentary agriculture. Periods of rapid sea-level rise before and after may have catalyzed significant postglacial episodes of human dispersal in coastal regions.
Drilling program investigates permafrost gas hydrates

On 25 December 2001, fieldwork began on a new gas hydrate research well program at the northeastern edge of the Mackenzie Delta, Northwest Territories, Canada (Figure 1, top). The Mallik research well program of 2001–2002 will drill a 1200-m deep main production research well, and, for the first time, two 1150-m-deep scientific observation wells offset 40 m from the main well (Figure 1, bottom) for geophysical monitoring of the main well. The science and engineering objectives are to assess the production properties of gas hydrates and determine the stability of continental gas hydrates both in terms of past climate warming events and in response to warming trends predicted by various climate change models.
Spectral Analysis of Randomly Generated Networks With Prescribed Degree Sequences

Network science attempts to capture real-world phenomenon through mathematical models. The underlying model of a network relies on a mathematical structure called a graph. Having seen its early beginnings in the 1950’s, the field has seen a surge of interest over the last two decades, attracting interest from a range of scientists including computer scientists, sociologists, biologists, physicists, and mathematicians. The field requires a delicate interplay between real-world modeling and theory, as it must develop accurate probabilistic models and then study these models from a mathematical perspective. In my thesis, we undertake a project involving computer programming in which we generate random network samples with fixed degree sequences and then record properties of these samples. We begin with a real-world network, from which we extract a sample of at least one-hundred vertices through the use of snowball sampling. We record the degree sequence, D, of this sample and then generate random models with this same degree sequence. To generate these models, we use a well-known graph algorithm, the Havel-Hakimi algorithm, to produce an initial non-random sample GD. We then run a Monte Carlo Markov Chain (MCMC) on the sample space of graphs with this degree sequence beginning at GD in order to produce a random graph in this space. Denote this random graph by HD. Lastly, we compute the eigenvalues of the Laplacian matrix of HD, as these eigenvalues are intricately connected with the structure of the graph. In doing this, we intend to capture local properties of the network captured by the degree sequence alone. The programming of this project is done in Python and Matlab.
An intercomparison of surface energy flux measurement systems used during FIFE 1987

During FIFE 1987, surface energy fluxes were measured at 22 flux sites by nine groups of scientists using different measuring systems. A rover Bowen ratio station was taken to 20 of the flux stations to serve as a reference for estimating the instrument-related differences. The rover system was installed within a few meters from the host instrument of a site. Using linear regression analysis, net radiation, Bowen ratio, and latent heat fluxes were compared between the rover measurements and the host measurements. The average differences in net radiation, Bowen ratio, and latent heat flux from different types of instruments can be up to 10, 30, and 20%, respectively. The Didcot net radiometer gave higher net radiation while the Swissteco type showed lower values, as compared to the corrected radiation energy balance system (REBS) model. The four-way components method and the Thornthwaite type give similar values to the REBS. The surface energy radiation balance systems type Bowen ratio systems exhibit slightly lower Bowen ratios and thus higher latent heat fluxes, compared to the arid zone evapotranspiration systems. Eddy correlation systems showed slightly lower latent heat flux in comparison to the Bowen ratio systems. It is recommended that users of the flux data take these differences into account.
A discrete numerical model for granular assemblies

The distinct element method is a numerical model capable of describing the mechanical behaviour of assemblies of discs and spheres. The method is based on the use of an explicit numerical scheme in which the interaction of the particles is monitored contact by contact and the motion of the particles modelled particle by particle. The main features of the distinct element method are described. The method is validated by comparing force vector plots obtained from the computer program BALL with the corresponding plots obtained from a photoelastic analysis. The photoelastic analysis used for the comparison is the one applied to an assembly of discs by De Josselin de Jong and Verruijt (1969). The force vector diagrams obtained numerically closely resemble those obtained photoelastically. It is concluded from this comparison that the distinct element method and the program BALL are valid tools for research into the behaviour of granular assemblies. La methode des elements distincts est un modele numerique capab.
Demarcation of potential avalanche sites using remote sensing and ground observations: a case study of Gangotri glacier

This study demonstrates the effectiveness of remote sensing and analytical hierarchy process for avalanche hazard mapping. The layers incorporated in this study were of slope, aspect, profile curvature, ground cover and elevation. The accuracy of output was determined using the registered avalanche sites based on ground observations and field-based modelling techniques. 93.35% of avalanche-affected areas came under maximum and moderate hazard zones, thus proving the effectiveness of this technique for Gangotri glacier basin. A parallel study was done to observe the change in the results, if any, by using high-resolution DEM and Cartosat-1 imagery. Similar methodology was adopted and the outcome was having significant improvement over the previous result as 98.8% of the preregistered avalanche area falling within maximum and moderate hazard zones.
North‐eastward subduction followed by slab detachment to explain ophiolite obduction and Early Miocene volcanism in Northland, New Zealand

Oligocene–Miocene models for northern New Zealand, involving south‐westward subduction to explain Early Miocene Northland volcanism, do not fit within the regional Southwest Pacific tectonic framework. A new model is proposed, which comprises a north‐east‐dipping South Loyalty basin slab that retreated south‐westward in the Eocene–earliest Miocene and was continuous with the north‐east‐dipping subduction zone of New Caledonia. In the latest Oligocene, the trench reached the Northland passive margin, which was pulled it into the mantle by the slab, resulting in obduction of the Northland allochthon. During and after obduction, the slab detached from the unsubductable continental lithosphere, inducing widespread calc‐alkaline volcanism in Northland. The new model further explains contemporaneous arc volcanism along the Northland Plateau Seamount Chain and sinking of the Northland basement, followed by uplift and extension in Northland.
Variability in the chlorophyll‐specific absorption coefficients of natural phytoplankton: Analysis and parameterization

Variability in the chlorophyll (chl) a-specific absorption coefficients of living phytoplankton aph*(λ) was analyzed using a data set including 815 spectra determined with the wet filter technique in different regions of the world ocean (covering the chlorophyll concentration range 0.02–25 mg m−3). The aph* values were observed to decrease rather regularly from oligotrophic to eutrophic waters, spanning over more than 1 order of magnitude (0.18 to 0.01 m2 mg−1) at the blue absorption maximum. The observed covariation between aph*(λ) and the field chl a concentration (chl) can be explained considering (1) the level or pigment packaging and (2) the contribution of accessory pigments to absorption. Empirical relationships between aph*(λ) and 〈chl〉 were derived by least squares fitting to power functions. These relationships can be used to produce aph* spectra as a function of 〈chl〉. Such a simple parameterization, if confirmed with further data, can be used, e.g., for refining estimates of the carbon fixation rate at global or regional scales, such as those obtained by combining satellite pigment concentration maps with primary production models based on physiological parameters, among which aph* is an important one.
Nonlinear Systems Analysis

Introduction. Non-linear Differential Equations. Second-Order Systems. Approximate Analysis Methods. Lyapunov Stability. Input-Output Stability. Differential Geometric Methods. Appendices: Prevalence of Differential Equations with Unique Solutions, Proof of the Kalman-Yacubovitch Lemma and Proof of the Frobenius Theorem.
North Pacific Storm Track Variations in Winter Season and the Coupled Pattern with the Midlatitude Atmosphere‐Ocean System

The North Pacific storm track variations in winter are investigated by using European ECMWF (ERA40) reanalysis data and Empirical Orthogonal Function (EOF) method. The coupled patterns between the time-mean flow anomaly and the sea surface temperature (SST) anomaly, related with the storm track variations are studied by regression method. It is shown that there are two major variation modes of the North Pacific storm track in winter. The first mode is characterized by northward (southward) shift of the mid-east part of the storm track that connotes a northeastward (southeastward) reorientation of the track. Meanwhile, in the mid-latitude North Pacific, the high (low) pressure anomaly is overlapped over the warm (cold) SST anomaly, displaying a warm-ridge (cold-trough) vertical structure, with negative phase of the Pacific-North American (PNA) pattern in the middle and upper troposphere. The second type denotes entirely intensified (weakened) and slightly northward (southward) storm track. It is associated with warmer (colder) SST in the Kuroshio region, northward (southward) shift both of the low-level Aleutian low and high-level westerly jet, and negative (positive) Western Pacific (WP) phase in the mid- and high troposphere. The time coefficients of storm track EOF have significant correlation with the Aleutian low index, PNA and WP indices, Nino-3 index and the Kuroshio SST index, respectively, which re-demonstrate the existence of the coupled pattern among the three selected fields: SST, storm track and large-scale time-mean flow anomalies.
Windows NT Thin Client Solutions: Implementing Terminal Server and Citrix MetaFrame

From the Publisher: A comprehensive treatment of implementation considerations, Windows NT Thin Client Solutions: Implementing Terminal Server and Citrix Metaframe is an invaluable resource for system architects, system engineers, and network administrators who are integrating thin client technology into their networks. This book is a critical resource to help you evaluate the potential benefits of thin client technology for your specific network environment. Each stage of implementation is covered in detail, including: Solutions for a wide variety of corporate networks, from single-server operations to multiple-server international enterprise networksExpert advice on determining desktop, client infrastructure, and wide area network requirementsVital information on integrating Citrix MetaFrame with Microsoft Terminal Server, a critical task for networks that use other operating systems in addition to Windows NT Authoritative material on how to successfully install, optimize, and troubleshoot applications in a multi-user environment
Observations of non‐volcanic tremor during the northern Cascadia slow‐slip event in February 2002

We locate in the Cascadia subduction zone non‐volcanic tremors from an episodic tremor and slip event in February 2002. The tremors occurred during two 10‐day periods separated by a short lull. Tremors that occurred during the first period are broadly distributed between 10 km and 40 km depth at the southern end of Vancouver Island, and over a >50 km wide region measured normal to the margin. During the second period of tremor activity, most tremors were concentrated in a narrower zone, and many tremors occurred near the subduction megathrust at approximately 35 km depth. This relatively large number of tremors near the subduction megathrust is in contrast to the broad depth distribution of the subsequent March 2003 tremor sequence. The change in the pattern of tremor activity observed during the February 2002 sequence may indicate a change in the slow slip process, or in its migration along the margin.
Internal layer tracing and age‐depth‐accumulation relationships for the northern Greenland ice sheet

Clues to previous ice sheet structure and long-term glaciological processes are preserved in the internal layering configuration of the Greenland ice sheet. Information about these internal layers has been retrieved over many parts of the ice sheet with the University of Kansas ice-penetrating radar. We report on the coherence of these layers over very large distances, describe a method of tracing these layers along thousands of kilometers of flight line, and do so for one flight during the 1999 Program for Arctic Regional Climate Assessment (PARCA) aircraft campaign. We determine the ages of these layers, based on information at the GRIP ice core site, and extend these ages along the flight line to Camp Century, where they are compared to modeled-derived age estimates. These ages agree with each other to between 2 and 15%, differences that can be substantially reduced with minor changes to the model parameters (accumulation rate and shear layer depth). Finally, we are able to derive estimates of accumulation rates along the flight line by fitting the age-depth data from layer tracing to a Dansgaard-Johnsen model with a minimization technique, providing estimates that match recent accumulation patterns within a few centimeters per year.
N2O emissions and carbon sequestration in a nitrogen‐fertilized Douglas fir stand

[1] This study investigated how nitrogen (N) fertilization with 200 kg N ha−1 of a 58-year-old West Coast Douglas fir stand influenced its net greenhouse gas (GHG) global warming potential (GWP) in the first year after fertilization. Effects of fertilization on GHG GWP were calculated considering changes in soil N2O emissions, measured using the static chamber technique and the soil N2O gradient technique; eddy covariance (EC) measured net ecosystem productivity (NEP); and energy requirements of fertilizer production, transport, and its aerial spreading. We found significant N2O losses in fertilized plots compared to a small uptake in nonfertilized plots. Chamber-measured N loss in the fertilized plots was about 16 kg N2O ha−1 in the first year, which is equivalent to 10 kg N ha−1 or 5% of the applied fertilizer N. Soil N2O emissions measured using the gradient technique, however, exceeded the chamber measurements by about 50%. We also compared a polymer-coated slow-release urea with regular urea and found that the former delayed N2O emissions but the year-end total loss was about the same as that from regular urea. Change in NEP due to fertilization was determined by relating annual NEP for the nonfertilized stand to environmental controls using an empirical and a process-based model. Annual NEP increased by 64%, from 326 g C m−2, calculated assuming that the stand was not fertilized, to the measured value of 535 g C m−2 with fertilization. At the end of the year, net change in GHG GWP was −2.28 t CO2 ha−1 compared to what it would have been without fertilization, thereby indicating favorable effect of fertilization even in the first year after fertilization with significant emissions of N2O.
Comparisons between buoy‐observed, satellite‐derived, and modeled surface shortwave flux over the subtropical North Atlantic during the Subduction Experiment

Two years of surface shortwave flux data, from five buoys in the subtropical North Atlantic Ocean during the Subduction Experiment, were used to examine shortwave absorption in the atmosphere, and its partitioning between the clear and cloudy sky. Robust methods were used to isolate the clear-sky shortwave observations so that they could be directly compared to values derived using a single-column version of the National Center for Atmospheric Research Community Climate Model radiation code. The model-derived values agreed with the observations to within 0.5% mean relative error. Additional analysis showed that the model-data clear-sky surface shortwave differences showed no systematic relationship with respect to column water vapor amount. These results indicate that clear-sky absorption of shortwave radiation appears to be well modeled by current theory. Model-derived clear-sky surface shortwave values were combined with the observed (all-sky) values to determine the surface shortwave cloud forcing. The mean of these series were combined with 5-year mean Earth Radiation Budget Experiment derived top of the atmosphere (TOA) cloud forcing values to estimate the surface to TOA cloud forcing ratio. The resulting values range between 1.25 and 1.59. These values, along with the agreement between modeled and observed clear-sky surface shortwave, support the suggestion that our current theoretical radiative transfer models do not properly account for the amount of shortwave energy absorbed by the cloudy atmosphere. Mean values from the 2-year shortwave flux time series were compared to mean values from two climatologies derived from bulk parameterizations that utilize ship-based cloud reports. These comparisons show that the Oberhuber climatology underestimates the surface shortwave flux by ∼20% (∼40 W m -2 ), while the Esbensen and Kushnir climatology underestimates the flux by ∼4% (∼8 W m -2 ). The observed mean values were also compared to five satellite-derived climatologies. These comparisons showed much better and more consistent agreement, with relative bias errors ranging from about -1 to 6%. Comparisons to contemporaneous, daily-average satellite derived values show relatively good agreement as well, with relative biases of the order of 2% (∼3-9 W m -2 ) and root-mean-square differences of ∼10% (25-30 W m -2 ). Aspects of the role aerosols play in the above results are discussed along with the implications of the above results on the integrity of open-ocean buoy measurements of surface shortwave flux and the possibility of using the techniques developed in this study to remotely monitor the operating condition of buoy-based shortwave radiometers.
Morphologic and morphometric analysis of adrenal gland cortex of sheep grazing on pastures with the ground of electrofilter ash

Electrofilter ash is a side product of power plants using coal as a fuel. Trials for transforming ash covered areas into cultivated landscape are ongoing e.g., efforts to form grasslands that would be usable for animal breeding and production. However the question of how safe grazing is on such surfaces in relation to animal health and the use of animal products, produced on such surfaces, for human consumption has not been truly resolved yet. The main goal of our work is a systematic search for the possible negative effects on animals grazing on such surfaces. In this work we present the results of morphologic and morphometric analyses that were made to evaluate the potential toxic or some other impact of electrofilter ash constituents on the adrenal gland cortex. No conclusive evidence of such effects was determined in this study.
Engineered Surface Barrier Monitoring Using Ground‐Penetrating Radar, Time‐Domain Reflectometry, and Neutron‐Scattering Techniques

Effective monitoring of surface barriers intended to isolate and protect waste from the accessible environment requires techniques to assess their performance. Quantifying drainage conditions at any point below the barrier is difficult because field‐scale drainage measurements are not well suited for assessing spatial drainage heterogeneity. Measurements of water storage, however, can provide an indirect measure of impending drainage. We measured seasonal water content at a vegetated capillary barrier on the Hanford Site in southeastern Washington to determine effective water‐storage monitoring methods. Measurements were made using ground‐penetrating radar (GPR) direct ground wave methods operating at 100 MHz. Simultaneous measurements using time‐domain reflectometry (TDR) and neutron‐scattering probe (NP) were used to determine the sampling depth of the GPR ground wave. The ground wave sampling depth increased only slightly with decreasing moisture content, ranging from 30 to 37.5 cm. The TDR measurements were made using permanently emplaced arrays, eliminating the need for repeated ground disturbance. All three methods showed similar seasonal responses, with the highest water contents observed during the winter months and decreasing through the summer. Unlike TDR and NPs, which are local‐scale measurements, GPR exhibited much greater spatial detail across the barrier surface. While measurement uncertainties exist with regard to the sampling depth and dispersive effects, our results indicate that GPR can be an effective and minimally invasive method for providing reasonable near‐surface estimates of soil water content changes within an engineered barrier.
Liquefaction Evaluation Procedure

A procedure for evaluating liquefaction susceptibility of a soil mass subjected to shear stress, such as in slopes, embankments, and foundations of structures, is presented. Liquefaction analysis is a stability analysis for which the shear strength in the numerator of the factor of safety equation is the undrained steady-state strength, and the denominator is the driving shear stress. The driving shear stress is the shear stress required to maintain static equilibrium. The undrained steady-state shear strength is a function only of the void ratio. Thus, one critical step of the procedure for liquefaction evaluation is the determination of the in-situ void ratio and the correction of laboratory-measured undrained steady-state strength to account for unavoidable changes in void ratio of the soil during sampling and testing. Dilative soils are not susceptible to liquefaction. Cyclic load tests are not required to evaluate the susceptibility to liquefaction.