Miracle-dz/UniFAR-FTUs huggingface dataset:
Inferring terrestrial photosynthetic light use efficiency of temperate ecosystems from space

[1] Terrestrial ecosystems absorb about 2.8 Gt C yr? 1, which is estimated to be about a quarter of the carbon emitted from fossil fuel combustion. However, the uncertainties of this sink are large, on the order of ±40%, with spatial and temporal variations largely unknown. One of the largest factors contributing to the uncertainty is photosynthesis, the process by which plants absorb carbon from the atmosphere. Currently, photosynthesis, or gross ecosystem productivity (GEP), can only be inferred from flux towers by measuring the exchange of CO2 in the surrounding air column. Consequently, carbon models suffer from a lack of spatial coverage of accurate GEP observations. Here, we show that photosynthetic light use efficiency (? ), hence photosynthesis, can be directly inferred from spaceborne measurements of reflectance. We demonstrate that the differential between reflectance measurements in bands associated with the vegetation xanthophyll cycle and estimates of canopy shading obtained from multiangular satellite observations (using the CHRIS/PROBA sensor) permits us to infer plant photosynthetic efficiency, independently of vegetation type and structure (r2 = 0.68, compared to flux measurements). This is a significant advance over previous approaches seeking to model global-scale photosynthesis indirectly from a combination of growth limiting factors, most notably pressure deficit and temperature. When combined with modeled global-scale photosynthesis, satellite-inferred ? can improve model estimates through data assimilation. We anticipate that our findings will guide the development of new spaceborne approaches to observe vegetation carbon uptake and improve current predictions of global CO2 budgets and future climate scenarios by providing regularly timed calibration points for modeling plant photosynthesis consistently at a global scale.
Health App Use Among US Mobile Phone Owners: A National Survey

Background Mobile phone health apps may now seem to be ubiquitous, yet much remains unknown with regard to their usage. Information is limited with regard to important metrics, including the percentage of the population that uses health apps, reasons for adoption/nonadoption, and reasons for noncontinuance of use. Objective The purpose of this study was to examine health app use among mobile phone owners in the United States. Methods We conducted a cross-sectional survey of 1604 mobile phone users throughout the United States. The 36-item survey assessed sociodemographic characteristics, history of and reasons for health app use/nonuse, perceived effectiveness of health apps, reasons for stopping use, and general health status. Results A little over half (934/1604, 58.23%) of mobile phone users had downloaded a health-related mobile app. Fitness and nutrition were the most common categories of health apps used, with most respondents using them at least daily. Common reasons for not having downloaded apps were lack of interest, cost, and concern about apps collecting their data. Individuals more likely to use health apps tended to be younger, have higher incomes, be more educated, be Latino/Hispanic, and have a body mass index (BMI) in the obese range (all P<.05). Cost was a significant concern among respondents, with a large proportion indicating that they would not pay anything for a health app. Interestingly, among those who had downloaded health apps, trust in their accuracy and data safety was quite high, and most felt that the apps had improved their health. About half of the respondents (427/934, 45.7%) had stopped using some health apps, primarily due to high data entry burden, loss of interest, and hidden costs. Conclusions These findings suggest that while many individuals use health apps, a substantial proportion of the population does not, and that even among those who use health apps, many stop using them. These data suggest that app developers need to better address consumer concerns, such as cost and high data entry burden, and that clinical trials are necessary to test the efficacy of health apps to broaden their appeal and adoption.
Late Quaternary vegetational and climatic change in the Popayan region, southern Colombian Andes

Late Pleistocene and Holocene vegetational and climatic change have been studied palynologically at a site at 1750 m elevation in the subandean vegetation belt near Popayan, in the southern Colombian Andes. Time control on the pollen record is based on six AMS 14 C ages, ranging from possibly Middle Pleniglacial time (around 50 000 yr BP) to 1092 6 44 yr BP. Because of the presence of two hiatuses only the Middle Pleniglacial and Late Holocene periods (the last 2300 yr BP) are represented. Pollen data indicate the presence of closed subandean forest during glacial time. Changes in the contribution of pollen originating from the uppermost and lowermost subandean forest belts, changes in the contribution of a number of other subandean forest taxa, and changes in species composition between the three pollen zones, suggest that the climate during the Middle Pleniglacial was markedly colder, and perhaps also wetter, than during the Late Holocene. Pollen assemblages from the Late Holocene indicate that the landscape has been affected by deforestation and agriculture since at least 2300 yr BP, but that human impact decreased in the last 780 yr BP. © 1998 by John Wiley & Sons, Ltd.
Densification and permeability reduction in hot‐pressed calcite: A kinetic model

Laboratory studies on hot isostatically pressed (HIP) calcite reveal that the evolution of porosity and permeability during mechanical compaction can be divided into two distinct regimes. At high porosities, permeability is related approximately to porosity raised to the third power. However, below a porosity called the crossover porosity, the power law relationship no longer applies, and permeability reduction is accelerated. At a porosity of ∼4%, permeability becomes too low to be measured, indicating that a percolation threshold has been reached. In previous studies the time evolutions of porosity and permeability were not predicted, and further, the crossover porosity was introduced as an empirical input parameter. In this study we developed a unified model combining crack healing with densification by power law creep to reproduce porosity evolution as a function of time. Both the healing and the creep are deterministically controlled by the pressure and temperature. Permeability can then be calculated by incorporating quantitative microstructural data (i.e., pore size distribution) into a three-dimensional cubic network model. We were able to reproduce the permeability-porosity relationship in hot-pressed calcite aggregates in both high- and low-porosity regimes. In particular, our model predicted a crossover porosity of ∼7% and a percolation threshold of ∼4%, both in a good agreement with the experimental data. However, we generally overestimated the absolute values of permeability. Because the model yielded correct absolute permeability values in the case when the pore size distribution was known, we suppose that at least part of the error arises from inadequate data for microstructure.
Hydrocarbon ratios during PEM‐WEST A: A model perspective

A useful application of the hydrocarbon measurements collected during the Pacific Exploratory Mission (PEM-West A) is as markers or indices of atmospheric processing. Traditionally, ratios of particular hydrocarbons have been interpreted as photochemical indices, since much of the effect due to atmospheric transport is assumed to cancel by using ratios. However, an ever increasing body of observatonial and theoretical evidence suggests that turbulent mixing associated with atmospheric transport influences certain hydrocarbon ratios significantly. In this study a three-dimensional mesoscale photochemical model is used to study the interaction of photochemistry and atmospheric mixing on select hydrocarbons. In terms of correlations and functional relationships between various alkanes, the model results and PEM-West A hydrocarbon observations share many similar characteristics as well as explainable differences. When the three-dimensional model is applied to inert tracers, hydrocarbon ratios andother relationships exactly follow those expected by simple dilution with model-imposed “background air,” and the three-dimensional results for reactive hydrocarbons are quite consistent with a combined influence of photochemistry and simple dilution. Analogous to these model results, relationships between various hydrocarbons collected during the PEM-West A experiment appear to be consistent with this simplified picture of photochemistry and dilution affecting individual air masses. When hydrocarbons are chosen that have negligible contributions to clean background air, unambiguous determinations of the relative contributions to photochemistry and dilution can be estimated from the hydrocarbon samples. Both the three-dimensional model results and the observations imply an average characteristic lifetime for dilution with background air roughly equivalent to the photochemical lifetime of butane for the western Pacific lower troposphere. Moreover, the dominance of OH as the primary photochemical oxidant downwind of anthropogenic source regions can be inferred from correlations between the highly reactive alkane ratios. By incorporating back-trajectory information within the three-dimensional model analysis, a correspondence between time and a particular hydrocarbon or hydrocarbon ratio can be determined, and the influence of atmospheric mixing or photochemistry can be quantified. Results of the three-dimensional model study are compared and applied to the PEM-West A hydrocarbon dataset, yielding a practical methodology for determining average OH concentrations and atmospheric mixing rates from the hydrocarbon measurements. Aircraft data taken below 2 km during wall flights east of Japan imply a diurnal average OH concentration of ∼3 × 106 cm−3. The characteristic time for dilution with background air is estimated to be ∼2.5 days for the two study areas examined in this work.
An Adjoint Analysis of the Meridional Overturning Circulation in an Ocean Model

Abstract Using the adjoint of a fully three-dimensional primitive equation ocean model in an idealized geometry, spatial variations in the sensitivity to surface boundary forcing of the meridional overturning circulation’s strength are studied. Steady-state sensitivities to diapycnal mixing, wind stress, freshwater, and heat forcing are examined. Three different, commonly used, boundary-forcing scenarios are studied, both with and without wind forcing. Almost identical circulation is achieved in each scenario, but the sensitivity patterns show major (quantitative and qualitative) differences. Sensitivities to surface forcing and diapycnal mixing are substantially larger under mixed boundary conditions, in which fluxes of freshwater and heat are supplemented by a temperature relaxation term or under flux boundary conditions, in which climatological fluxes alone drive the circulation, than under restoring boundary conditions. The sensitivity pattern to diapycnal mixing, which peaks in the Tropics is similar.
Enderby land, Antarctica—an unusual Precambrian high‐grade metamorphic terrain

Abstract The high‐grade metamorphic rocks of Enderby Land, which form part of the East Antarctic Precambrian Shield, have been subdivided into two major metamorphic complexes—the Archaean Napier Complex and the Proterozoic Rayner Complex. The Napier Complex consists predominantly of pyroxene‐quartz‐feldspar gneiss and garnet‐quartz‐feldspar gneiss, with subordinate mafic granulite, pyroxenite, and a variety of siliceous, aluminous, and ferruginous metasediments. The gneisses are intruded by several types of mafic dyke, including an abundant suite of dolerites, the Amundsen Dykes, and locally by granitic rocks and pegmatite. Much of the Rayner Complex probably represents re‐metamorphosed Napier Complex rocks, and mafic dykes occur only as metamorphosed relics. The Rayner Complex is correlated with the Proterozoic metamorphics of the MacRobertson Land coast and northern Prince Charles Mountains, for which Rb‐Sr dates of 800–1100 m.y. have been obtained. Temperatures of at least 950°C, at pressures of 8–10 k.
Dynamical properties of a buoyancy-driven coastal current

The outflow of buoyant waters from major estuaries affects the dynamics of inner continental shelves profoundly as lateral density gradients force an alongshore current. Often the Coriolis force causes the outflow to remain trapped near the coast. We observed one such current, the Delaware Coastal Current, on the inner shelf near the Delaware Estuary on the eastern seaboard of the United States. The spatial variability along the shelf, however, suggests at least two dynamically distinct regions that we term source and plume regions. In the source region we find fronts, a current whose width scales well with the internal deformation radius, and a ratio of relative to planetary vorticity that reaches unity, that is, the Rossby number is O(1). As nonlinear inertial forces in the across-shelf momentum balance are weak, we suggest that such forces contribute to the along-shelf momentum balance only. Farther downstream in the plume region, we find much reduced lateral density gradients, a current much wider than the deformation radius, and relative vorticities that are much smaller than the planetary vorticity. From our observations we compute nondimensional dynamical parameters, with which we discuss our observations. The Burger, Rossby, and Ekman numbers for the Delaware Coastal Current suggest that most models of buoyancy-driven coastal currents do not apply to this coastal flow.
Use of Vanes for Control of Scour at Vertical Wall Abutments

Rock vanes are single-arm structures angled to the flow with a pitch into the streambed such that the tip of the vane is submerged even during low flow. Vanes have primarily been used in recent years for treatment of bank erosion in stream stability projects. These structures roll the water away from the eroding banks, thus limiting erosion of the channel banks. They have proven to be very effective treatments over a range of flow conditions. In this project, the effectiveness of vanes for preventing scour at single-span bridges with vertical wall abutments was evaluated based on laboratory experiments. The vanes were tested in small-scale experiments in a recirculating flume and subjected to a range of flow conditions, including bank full and a number of overbank flows, which were forced to return to the channel at the abutment. The results showed that the vanes were highly effective in moving the scour away from the abutment into the center of the channel under all flow conditions tested. Based on the experimental results, optimum design settings for the vane angle and height, most effective number of vanes, and distance upstream for placement of the first vane were determined.
Trans-Pacific Bathymetry Survey crossing over the Pacific, Antarctic, and Nazca plates

We carried out underway geophysical survey in the transit of the JAMSTEC R/V Mirai MR08-06 Leg-1. The cruise was an unprecedented opportunity to collect data in regions of the Pacific Ocean where it has sparsely been surveyed. Our multibeam bathymetric and shipboard gravity survey track crossed over the Pacific, the Antarctic, and the Nazca plates, and covered lithospheric ages varying from zero to 150 Ma. The survey revealed kilometer-sized fine-scale structures of seafloor fabrics; i.e. abyssal hills and fracture zones, and distribution of seamounts or knolls. These are not detectable in satellite altimetry data only. As well as contributing to the world's seafloor mapping, our survey results also show valuable evidence towards the plate tectonic reconstruction and help us look into the oceanic lithosphere formation and evolution, since the directions of tectonic stress and seafloor spreading mode are the major factors that can affect the morphology of lineated abyssal hills, etc.
Earthquake Response of Reinforced Segmental Retaining Walls Backfilled with Substantial Percentage of Fines

AbstractThis paper reports on the seismic performance of three geosynthetic-reinforced segmental retaining wall systems backfilled with a silty sand mixture, using a shaking table excited by 1995 Kobe earthquake loadings. The preparation of the backfill mixture and its properties, the tested wall configurations, the reinforcement layouts and instrumentations, and the observed wall performance are described. Visual observations and test results indicate that walls having 0.4-m vertical reinforcement spacing, backfilled with soil containing a large percentage of fines, performed better than those having good-quality sandy soil under otherwise identical conditions. Vertical spacing of 0.8 m with removal of interlocking facing blocks in one of the walls did not lead to global collapse under repeated applications of the Kobe earthquake loadings. Only localized shear failure behind the top block layer was observed as the top facing blocks tended to topple. The good performance was attributable to apparent cohes.
LENDING TO THE BORROWER FROM HELL : DEBT AND DEFAULT IN THE AGE OF PHILIP II , 1556 – 1598 *

Philip II of Spain accumulated debts amounting to nearly 60% of GDP. He also failed to honor these debts on four occasions. We ask what allowed the sovereign to borrow much while defaulting often. Earlier work emphasized either banker irrationality or the importance of sanctions, in line with Bulow and Rogoff (1989a). Using a unique data set on 438 lending contracts derived from the archives, we show that neither interpretation is supported by the evidence. What sustained lending was the ability of bankers to cut off Philip II’s access to smoothing services. Lenders contracted with the king in overlapping syndicates, effectively creating a network of bankers. We analyze the incentive structure that supported the cohesion of this bankers’ coalition and examine how it survived across the biggest defaults in Philip’s reign. In particular, we argue that the effectiveness of lending moratoria was sustained through a “cheat the cheater” mechanism in the spirit of Kletzer and Wright (2000). Since the king needed to spend before taxes arrived, in a context of major revenue and spending shocks, the ability of bankers to cut him off from funding was sufficient to sustain cross-border lending. We thank Carlos Alvarez Nogal, Fernando Broner, Michael Burda, Ann Carlos, Sir John Elliott, Oscar Gelderblom, Phil Hoffman, Hugo Hopenhayn, Ken Kletzer, Michael Kremer, Andreu Mas-Colell, Leandro Prados de la Escosura, Emilia Simeonova, Chris Sims, Jaume Ventura, Mark Wright, and Jeromin Zettelmeyer as well as seminar participants at Caltech, Stanford, UC Berkeley, UC Davis, Universidad Carlos III, UBC, Humboldt University, UPF, the 2008 Canadian Network for Economic History Conference, the CREI-CEPR Conference on Sovereign Risk, the Finance and History Conference at the University of Utrecht, and the History of Public Finances workshop at the Paris School of Economics. We also thank Marcos Agurto, Hans-Christian Boy, Diego Pereira Garmendía, Germán Pupato, Javier Torres, Cristian Troncoso-Valverde, and Anthony Wray for research assistance. Financial support from SSHRCC, TARGET/INE, the Spanish Ministry of Education, CREA, and a UBC AURA award is gratefully acknowledged.
Pliocene Model Intercomparison Project (PlioMIP): experimental design and boundary conditions (Experiment 1)

Abstract. In 2008 the temporal focus of the Palaeoclimate Modelling Intercomparison Project was expanded to include a model intercomparison for the mid-Pliocene warm period (3.29–2.97 million years ago). This project is referred to as PlioMIP (Pliocene Model Intercomparison Project). Two experiments have been agreed upon and comprise phase 1 of PlioMIP. The first (Experiment 1) will be performed with atmosphere-only climate models. The second (Experiment 2) will utilise fully coupled ocean-atmosphere climate models. The aim of this paper is to provide a detailed model intercomparison project description which documents the experimental design in a more detailed way than has previously been done in the literature. Specifically, this paper describes the experimental design and boundary conditions that will be utilised for Experiment 1 of PlioMIP.
Gully initiation and road-to-stream linkage in a forested catchment

This study reports the nature of sediment delivery pathways and road-to-stream linkage in a forested catchment in southeastern Australia, and evaluates the causal factors associated with this linkage. Detailed field surveying of approximately 20 per cent of the 75 km road network reveals that 18 per cent of road drains show complete channel linkage via gully development from a road outlet to a stream. An additional 11 per cent of road drains show evidence of partial channel linkage where the gully does not extend the full hillslope length. Inclusion of the full range of road-to-stream linkage categories, including direct linkage at stream crossings, road bridges and fords, results in a 6 per cent increase in drainage density since initial road construction in 1964. The majority of this linkage is associated with relief culverts draining cut-and-fill roads in mid-valley positions. These drainage structures have contributing road lengths that are on average three times longer than those draining mitre drains on ridgetop roads. Runoff from these roads is also discharged onto hillslopes that are at least twice as steep as those used on ridgetop roads. Contributing road length (m) and the gradient of the discharge hillslope (tan θ) are successfully used here in a linear discriminant analysis to separate channelled and non-channelled flow pathways within the catchment. The successful delineation of these pathways using two easily measured variables suggests that this approach has potential in the planning and rehabilitation of forest roads. Copyright © 2001 John Wiley & Sons, Ltd.