Miracle-dz/UniFAR-FTUs huggingface dataset:
Exorcising the `segment length curse': summer temperature reconstruction since AD 1640 using non-detrended stable carbon isotope ratios from pine trees in northern Finland

Stable carbon isotope ratios from the latewood cellulose of 12 trees from two sites in northern Finland are used to construct an isotope chronology covering AD 1640 to 2002. By measuring isotopic ratios of every sample independently it is possible to identify and remove the juvenile portion of each δ 13C series, correct the individual series for anthropogenic changes in atmospheric carbon dioxide isotopic ratios and concentrations, and to quantify changes in signal strength through time. Most importantly, it is possible to demonstrate that there are no long-term trends in the carbon isotope series that are related to tree age. This means that it is not necessary to detrend the series and so they have the potential to retain climate information at all temporal frequencies. The correlation between the non-detrended carbon isotope series and July/August mean temperature is high (r=0.72) and comparison with meteorological records suggests that the dominant control over tree ring δ13C at these high latitude, moist sites is photosynthetic rate rather than stomatal conductance. Summer temperature reconstructions based on three different calibrations are presented, with verification based on a mixture of jacknife and split period designs, providing robust and near identical results. Reconstructed late summer temperatures in the early 1900s are very low but the years centred around AD 1660 and 1760 appear to have experienced warmer summers than the late twentieth century, thus our late summer reconstruction does not show a recent warming trend. Our results are in agreement with other palaeoclimate reconstructions for northern Fennoscandia, which show late twentieth-century warming occurring predominantly in the winter. Our results suggest that, where replication and common signal strength are sufficiently high, stable carbon isotope dendroclimatology may provide high resolution proxy time series that also record climate information at lower temporal frequencies, thus avoiding the `segment length curse' that can apply to palaeoclimate reconstructions based on other tree ring parameters such as ring widths and density.
Evaluating Health Care Externality Costs Generated by Risky Consuption Goods

We present an overlapping-generations (OLG) macroeconomic model that applies a behavioral interpretation of preferences for goods that generate health risks. In this paper proneness to poor health is viewed as a cognitive miscalculation by economic agents between their expected health state over various consumption bundles and the actual health care they require for their health outcome. To model this the paper borrows insight from prospect theory and applies the reference-dependent preference framework to the specification of out utility model. In our model of the economy individual preferences are decomposed into intrinsic consumption utility and gain-loss utility associated with the miscalculation. Agents in the economy are stratified in their health states as well as their expected health care consumption according to some probability measure over the population. Heterogeneity introduced in this way generates consumers of varied proneness to risk associated with consumption of unhealthy goods because individuals have various marginal valuations of their miscalculation. In such a population, when all agents pay the same insurance premium, health-conscious agents shoulder the health care costs of their less health-conscious counterparts and the less health-conscious are engaged in less healthy consumption than they would if they paid actuarially fair premia. We demonstrate these effects in simulations by comparing the risk pooling equilibria to the actuarially fair pricing equilibria. This paper introduces the mathematical programming equilibrium constraint (MPEC) computational approach to compute model equilibria; we believe this approach is new to heterogeneous agent OLG model simulation.
Spatial and temporal distributions of magnetic effects of auroral electrojets as derived from AE indices

In deriving auroral electrojet 2.5-min. magnetic activity indices for 1970, simple statistics were kept that tabulated the time and frequency of contribution of index values by each of the 11 geomagnetic observatories whose records were used in the derivation. Systematic patterns were noted in the times of most frequent observation of extreme H deviations by each station for both quiet and disturbed hours. On the average, AL was most often derived from records of stations located about 3 1/4 hours past local geomagnetic midnight, LGM (peak westward electrojet effect); a second prominent time of occurrence of extreme negative H values came at 11 1/4 hours after LGM; AU was most often derived from stations located 6 1/2 hours before LGM (peak eastward electrojet effect); and a second prominent time of occurrence of extreme positive H values came at about 6 1/4 hours after LGM. The secondary peak times of index contribution are shown to be consistent with quiet time current sources apparently equatorward of the auroral zone. The UT daily pattern of average hourly values of AU is shown to vary seasonally, being lowest in winter, intermediate during equinoctial months, and highest during summer. No clear diurnal UT dependence canmore » be seen in disturbed hour averages of AU. The average hourly AL values for disturbed hours are not clearly differentiated by season but appear to have a broad span of higher values from 1200 to 2100 UT. A composite map is included of regions within which auroral electrojet currents would produce the systematic extreme H deviations revealed in the derivation of 1970 AE(11). Preliminary analyses of AE indices for 1966 through 1971 give results that agree with these conclusions. « less
Two‐Phase Flow Visualization and Relative Permeability Measurement in Natural Rough‐Walled Rock Fractures

A laboratory flow apparatus was used to visualize and measure two-phase gas-liquid flows in natural rough-walled rock fractures. Experiments at carefully controlled flow rate and pressure conditions have been performed using a natural fracture and three transparent fracture replicas. Two-phase flow exhibited persistent instabilities with cyclic pressure and flow rate variations even under conditions of constant applied boundary conditions. Visual observations of changes in pore occupancy showed that the instabilities could be explained as resulting from an interplay between capillary effects and pressure drop due to viscous flow. Measurements of relative permeabilities indicated strong phase interference, with relative permeabilities reduced to very small values at intermediate saturations for both wetting and nonwetting phases. These results run counter to a conventional view of fracture relative permeabilities that assumes that the relative permeability of each phase is equal to its saturation, but the results are consistent with recent models that view fractures as two-dimensional heterogeneous porous media. 35 refs., 10 figs., 1 tab.
Integrating a Trusted Computing Base Extension Server and Secure Session Server into the LINUX Operating System

Abstract : The Multilevel Secure Local Area Network (MLS LAN) Project at the Naval Postgraduate School's Center for Information Security (INFOSEC) Studies and Research (NPS CISR) is building a trusted network system that is both necessary and sufficient to provide a multilevel networking solution for real world use. The current configuration provides the necessary trusted network services on the TCSEC Class B-3 evaluated XTS-300, which is a combination of the STOP version 4.4. 2 multilevel secure operating system, and a Wang-supplied Intel x86 hardware base. The interface for the STOP operating is based on the System V.3 UNIX implementation System V.3 lacks many of features available in more modern UNIX implementations such as System V.4 and BSD 4.3, and also lacks many of the features in POSIX and ANSI C standards, Finally, the CPU is several generations older than the more current Intel processors. This thesis discusses the port of several MLS trusted network services on the XTS-300 to a Linux operating system running on an Intel Pentium Processor, The new Linux TCBE Server configuration will permit further experimentation with MLS architectural issues in a more modern, flexible and easily modifiable environment The port was accomplished by identifying and modifying the necessary software modules needed, to adapt to a Linux environment This thesis proves that XTS-300 TCB services can be ported to Linux system without any negative effects on performance thus allowing a move toward a more security enhanced implementation.
APPLICATION OF SWAT FOR IMPACT ASSESSMENT OF LAND USE/COVER CHANGE AND BEST MANAGEMENT PRACTICES: A REVIEW

Globally, the quantification and evaluation of land use and cover changes on the hydrological status of river basins is a main concern. There is an urgent need for technologies and models that can quantify the impact of land use change and management practices in an organized manner. Approach: Soil and Water Assessment Tool (SWAT) integrated with Geographic Information System (GIS) has great potential in current estimation, future prediction and proper decision making in terrestrial ecosystems. This review discusses the current utilization of SWAT in impact assessment of land use/cover change and best management practices. Results: Deployment of SWAT and land use/cover simulation models for impact assessment improves accuracy, reduces costs, and allows the simulation of a wide variety of conservation practices at watershed scale. Conclusion: This review demonstrates the synergistic role of SWAT and GIS technologies in improving watershed management.
Multivariate approach for chlorophyll-a and suspended matter retrievals in Case II type waters using hyperspectral data

Abstract Remote sensing has become promising in providing temporal and spatial information on biogeodynamics in large and open freshwater bodies. In optically complex environments, such as in the Western Basin of Lake Erie (WBLE), the water contains multiple biogeochemical constituents or colour producing agents (CPAs), such as phytoplankton, suspended matter and dissolved organic carbon; identifying and analysing such in-water constituents is crucial for understanding and assessing many biogeochemical processes. For example, concentrations of chlorophyll-a and total suspended matter can be used as proxies to assess phytoplankton dynamics and particulate loading. However, quantitative estimation of their concentrations from satellite observations is complicated when working with mixed spectral signatures. Hyperspectral remote sensing is fast emerging as a key technology for advanced and improved understanding of optically complex waters. This study estimates concentrations of chlorophyll-a and total suspended matter (TSM) in the WBLE by applying the partial least squares (PLS) method to a full range (400–900 nm) of continuous narrow spectral bands. The PLS method models the covariance between hyperspectral bands and CPAs, and identifies the optimal bands that characterize most of the variance in the CPAs. This method avoids the curse of dimensionality and the effects of multi-collinearity, a challenge that is associated with new-generation hyperspectral satellite sensors. Validation parameters for the PLS-based models produced R2 of 0.84 for chlorophyll-a (RMSE = 1.18 μg/L), and R2 of 0.90 for TSM (RMSE = 1.26 mg/L), illustrating the potential of the PLS method for isolating and extracting absorption features characterizing the various CPAs in optically complex Case II type waters. Editor Z.W. Kundzewicz Associate editor Not assigned
Geology of the De Queen Formation of Arkansas

ABSTRACT Beds of the De Queen Formation are exposed in gypsum quarries within Pike and Howard Counties, Arkansas. The formation lies within the Lower Cretaceous Trinity Group which crops out in an east-west band across southwestern Arkansas. The De Queen Formation consists of a lower sulphate facies and an upper predominantly siliciclastic facies. The lower facies is approximately 40 ft (12 m) thick and is composed of interbedded gypsum, claystone, and limestone. This lower facies is equivalent to the subsurface Ferry Lake Anhydrite of the Gulf Coastal Plain. The upper facies is also approximately 40 ft (12 m) thick and contains interbedded clastics, limestones, and minor evaporites. Upper beds of the De Queen are equivalent to the lowermost beds of the subsurface Mooringsport Formation. During Ferry Lake-De Queen time a wide lagoon was located behind an extensive reef stretching around the Early Cretaceous shelf edge. This reef formed a barrier which restricted circulation and led to the deposition of the gypsum beds of the De Queen Formation and the Ferry Lake (later recrystallized to anhydrite during burial). Individual evaporite beds may be traced downdip from the outcrop across southern Arkansas into Louisiana and Texas. The regional extent of these evaporite beds reflects the variable geographic breadth of the lagoon during deposition of the Ferry Lake. Gypsum beds of the outcrop are the equivalent of the more widespread anhydrite beds of the Ferry Lake Anhydrite. Faunal assemblages, sedimentary structures, and trace fossils, which include a large number of dinosaur tracks, are important to the interpretation of depositional environments of rocks of the De Queen Formation. Much of the lower half of the formation was deposited in a shallow-subaqueous setting, while depositional environments of beds within the upper half of the De Queen varied between subaqueous and exposed conditions.
Simultaneous VHF auroral backscatter measurements

Simultaneous auroral echoes at 49.7, 143.5, and 226 Mc/s have been recorded using scaled radar equipments. Analysis indicates that the wavelength dependence of auroral echoes varies from λ3. 5 for frequencies of 49.7 and 143.5 Mc/s to λ6. 5 for frequencies of 143.5 and 226 Mc/s. These measurements are in reasonable agreement with Booker's theory of auroral echoes if the scale sizes (measured transverse to the magnetic field) are taken as roughly 40 cm. Evidence for nondeviative absorption at 50 Mc/s is also adduced.
On the Relationship between Particle Breakage and the Critical State of Sands

ABSTRACT Ring shear and shear box tests were used to investigate the relationship between volume change and particle breakage during the shearing of two sands. One sand was a carbonate sand which was sheared under a high confining stress to examine whether, in the region of compressive shearing behaviour due to particle breakage, the breakage would ever cease and the soil reach a stable grading. The other sand tested was a quartz sand that was sheared at low confining stresses, to investigate whether a dilatant sand would also be subject to particle breakage. In both cases breakage was found to continue to very large strains, with no evidence of a stable grading being reached within the range of strains used. While the breakage was very small for the quartz sand it was large for the carbonate, emphasising that any definition of a critical state by means of conventional triaxial or shear box testing would be approximate only, because of the limited strains that they allow.
Planktic foraminiferal sedimentation and the marine calcite budget

The vertical flux and sedimentation rate of planktic foraminiferal tests are quantified and a global planktic foraminiferal CaCO3 budget is presented. Test and calcite flux rates are calculated according to the distribution of species obtained from multinet and sediment trap samples. Modern planktic foraminiferal population dynamics are discussed as a prerequisite for the quantification of the calcite budget, highlighting the importance of ecological, autecological (e.g., reproduction), and biogeochemical conditions that determine the presence or absence of species. To complete the open‐marine, particulate CaCO3 inventory, the contribution of coccolithophores, pteropods, and calcareous dinophytes is discussed. Based on the studied regions, the global planktic foraminiferal calcite flux rate at 100 m depth amounts to 1.3–3.2 Gt yr−1, equivalent to 23–56% of the total open marine CaCO3 flux. The preservation of tests varies on a regional and temporal scale, and is affected by local hydrography and dissolution. During most of the year (off‐peak periods), many tests dissolve above 700‐m water depth while settling through the water column, with on average only 1–3% of the initially exported CaCO3 reaching the deep‐seafloor. Pulsed flux events, mass dumps of fast settling particles, yield a major contribution of tests to the formation of deep‐sea sediments. On average, ∼25% of the initially produced planktic foraminiferal test CaCO3 settles on the seafloor. The total planktic foraminiferal contribution of CaCO3 to global surface sediments amounts to 0.36–0.88 Gt yr−1, ∼32–80% of the total deep‐marine calcite budget.
Temporal and spatial variability of frost‐free seasons in the Great Lakes region of the United States

The frequency and timing of frost events and the length of the growing season are critical limiting factors in many human and natural ecosystems. This study investigates the temporal and spatial variability of the date of last spring frost (LSF), the date of first fall frost (FFF), and the length of the frost‐free season (FFS) in the Great Lakes region of the United States using two gridded reanalysis datasets for the period of 1980–2010. Across most of the Great Lakes region, there has been a negative trend for the LSF and a positive trend for the FFF, leading to a lengthening of FFS. The three variables vary spatially across the region and exhibit large interannual variability. Empirical orthogonal function (EOF) analyses indicate that the first mode for the three variables, which accounts for about 30% of the total variance, is in phase across most of the Great Lakes region and that it appears to be related to Pacific North American (PNA) pattern in the case of LSF and to Pacific Decadal Oscillation (PDO) in the case of FFF and FFS. The main reason for these connections is that the 200‐hPa geopotential height anomaly over North America induced by a Rossby wave train influences the strength of the trough over North America, which in turn affects surface temperatures over the Great Lakes region. The second mode, explaining about 10% of the total variance, mainly shows the out‐of‐phase variability between the Great Lakes and the surrounding land and it appears to be related to the circumglobal teleconnection (CGT) in the case of LSF and again to PDO in the case of FFF and FFS.
Ground truth requirements for radar observations over land and seat

Abstract At a first stage of development, ground truth is gathered in conjunction with radar data in order to establish statistical correlations between observed backscatter and properties of the irradiated surface. Significant correlations have been shown to exist between backscatter and many geophysical quantities; for example scatterometer measurements over the ocean can be used to infer wind speed, synthetic aperture radar (SAR) measurements over woodland can allow the separation of tree species, etc. Once statistical relationships are established, the next stage is to try to understand the physics underlying the relationship, both because of its intrinsic interest and because of the need to optimize system performance for particular applications. This places a second role on ground truth, since it must be used to validate the physical theories stemming from it. Microwave scattering from land surfaces is a topic of growing interest as we look towards land observation missions within the coming decade.
Secondary Frequency Control for Reconfigurable Interconnecting Microgrids

Microgrids and microgrid technologies offer an operations and control framework for realizing the needed aggregation of a growing share of distributed energy resources. As the number of microgrids increases, so will the incentive to interconnect them, leading to a combinatorial growth of potential operating states. At the same time, their growing complexity nudges interconnected microgrids conceptually closer to balancing authorities in the bulk power system. This paper focuses on secondary frequency control and leverages the conceptual similarity between balancing authorities and interconnected microgrids to adopt an automatic generation control design with some adaptations. Frequency control and restoration is demonstrated via several use-cases with switching and reconfiguration events.
Activation volume of Si diffusion in San Carlos olivine: Implications for upper mantle rheology

The effect of pressure on silicon diffusion in San Carlos olivine has been determined using a uniaxial split-sphere apparatus (USSA-2000) and the nuclear reaction analysis technique (NRA) on the 30Si isotope. Experiments were performed at high temperature, T = 1763 K, and pressures between 4 and 9 GPa. The specimens were inserted into a pure Fe capsule, which is very effective in maintaining the oxygen fugacity within the stability field of olivine, as well as providing a soft medium to mechanically protect the crystals. Diffusion profiles along the b→ crystallographic axis and of characteristic length of the order of 50 nm were obtained after annealing the olivine samples between 1 and 4 hours. We find the activation volume for silicon diffusion in San Carlos olivine to be VSi = +(0.7±2.3) × 10−6 m3/mol after a correction for oxygen fugacity which is pressure-dependent. This result demonstrates that pressure has practically no effect upon silicon diffusion under our temperature and pressure conditions. Extrapolation of our high-pressure measurements to 1 atm gives a Si diffusion coefficient, log(DSi) = −18.9±1.0 (with DSi in m2/s). Finally, our experiments show that according to the point-defect model of Jaoul [1990], the activation volume for creep of olivine at high temperature is dominated by the effect of pressure on the Mg defect concentration and has an activation volume close to 6 × 10−6 m3/mol.
Thermospheric gravity waves in the southern polar cap from 5 years of photometric observations at Davis, Antarctica

Five years of photometric data of the λ630 nm oxygen auroral/airglow emission (∼240-km altitude) over Davis, Antarctica (Λ=−74.6°), are searched for evidence of periodic oscillations due to atmospheric gravity waves. Data were selected for intervals when the auroral oval was equatorward of Davis and hence are from the thermospheric polar cap. A total of 106 cloud-free nights, each with a minimum of 2 hours in the cap, were subjected to a full spectral analysis. Wave-like features were seen on 45 nights (42%), with some nights showing evidence for two intervals of waves: A total of 53 waves were identified. Periods range from ∼13 to 40 min. We identify the oscillations as the signatures of gravity waves. Derived wave properties include horizontal wavelengths from 220 to 1600 km and phase speeds ranging from ∼200 to ∼850 ms−1. Around half of the waves are directed within ∼ ±40° of magnetic south, with most of the remainder being directed either approximately magnetic east or magnetic west. We interpret this as indicating the wave source regions are of significant linear extent and are aligned either parallel or perpendicular to the auroral oval. Source locations are estimated using the known dependence on frequency of the gravity wave angle of ascent, assuming the source is near the electrojet height (120 km) and ignoring the effects of background winds. The source locations are found to be near the magnetic latitude of the poleward edge of the auroral oval. Phase speeds and travel directions are similar to the speeds and direction of substorm surges, which is suggestive of the source of these waves.