Miracle-dz/UniFAR-FTUs huggingface dataset:
Long-term forest dynamics at Gribskov, eastern Denmark with early-Holocene evidence for thermophilous broadleaved tree species

We report on a full-Holocene pollen, charcoal and macrofossil record from a small forest hollow in Gribskov, eastern Denmark. The Fagus sylvatica pollen record suggests the establishment of a small Fagus population at Gribskov in the early Holocene together with early establishment of other thermophilous broadleaved trees, including Quercus sp. , Tilia sp. and Ulmus sp. The macrofossils contribute to the vegetation reconstruction with evidence for local presence of species with low pollen productivity or easily degraded pollen types such as Populus. The charcoal record shows frequent burning during two periods of the early Holocene and from c. 3000 cal. BP to present. The early-Holocene part of the record indicates a highly disturbed forest ecosystem with frequent fires and abundant macrofossils of particularly Betula sp. and Populus sp. The sediment stratigraphy and age–depth relationships give no clear indication of post-depositional disturbance, although a possible short-lived hiatus occurs around 6500 cal. BP. The early pollen record from thermophilous trees could indicate that there may have been some downwash following sediment desiccation through wood peat layers deposited between c. 6500 and 10,000 cal. BP, but the overall biostratigraphy is consistent with other Danish small hollow records.
The transverse momentum dependent distribution functions in the bag model

Leading and subleading twist transverse momentum dependent parton distribution functions (TMDs) are studied in a quark model framework provided by the bag model. A complete set of relations among different TMDs is derived, and the question is discussed how model-(in)dependent such relations are. A connection of the pretzelosity distribution and quark orbital angular momentum is derived. Numerical results are presented, and applications for phenomenology discussed. In particular, it is shown that in the valence-x region the bag model supports a Gaussian Ansatz for the transverse momentum dependence of TMDs.
Modeling and analyzing observed transverse sand bars in the surf zone

[1] A morphodynamic model has been applied to explain the characteristics of transverse sandbars observed in the inner surf zone of open beaches. The model describes the feedback between waves, rollers, depth-averaged currents and bed evolution, so that self-organized processes can develop. The modeled bar characteristics, i.e. wavelength (30–70 m), crest orientation (up-current) and the e-folding growth time (about 12 hr) are in good agreement with those of observed transverse bars at Noordwijk beach, the Netherlands, but modeled migration speeds (tens of meters per day), turn out to be a factor 2 larger than those observed. The wavelength increases with the distance between the shoreline and the peak of the longshore current and the migration speed is correlated with the maximum longshore current. The model also explains why transverse bar formation at Noordwijk occurs for obliquely incident waves of intermediate heights. Realistic positive feedback leading to formation of up-current oriented bars like those observed is only obtained if a term related to the turbulence sediment resuspension created by the rollers is included in the transport formula. In that case, the depth-averaged sediment concentration decreases seaward across the inner surf zone, enhancing the convergence of sediment transport in the offshore directed flow perturbations that occur over the up-current bars. This offshore current deflection is mainly caused by frictional torques, but the roller radiation stresses also play an important role.
Advective transport caused by intraseasonal Rossby waves: A key player of the high chlorophyll variability off the Peru upwelling region

[1] The upwelling region off Peru between 5°S and 12°S is characterized by high offshore intraseasonal variability in sea-surface productivity due to westward propagating chlorophyll anomalies, whose magnitude can reach half the variance of total chlorophyll variations. Spectral analyses of SSH, SST and chlorophyll satellite data show that these events are generated by intraseasonal Rossby waves. The almost constant phase shift between chlorophyll and altimetric signals suggests a physical mechanism dominated by horizontal advection, which is confirmed by the use of a simple conceptual model. Furthermore, an increase from the north to the south in the detected Rossby wave periods, correlated with a decrease in the wavelengths and phase velocities of the wave, suggests the presence of a second baroclinic mode north of 8°S and of a first baroclinic mode south of this latitude. The latitude of this transition is consistent with the theory of critical latitudes, which specifies that at a given latitude, only Rossby wave with periods below a threshold period, depending on the baroclinic structure of the wave, can propagate offshore. According to this theory, second baroclinic mode Rossby waves with periods greater than 130 days are supposed to propagate off the South American coast north of 8°S, the corresponding critical latitude.
An optical and hydrographic study of a temperature inversion off Oregon during upwelling

Optical and hydrographic measurements made in June 1967 during upwelling along the Oregon coast showed a temperature inversion starting 3 km from the shore and extending to 13 km from the shore. The thermal inversion was accompanied by a turbidity maximum in the permanent pycnocline. The mechanism for the formation of the temperature inversion and turbidity maximum appears to be cold, saline water upwelling from beneath the permanent pycnocline to the surface close to the coast, absorbing heat, and becoming biologically productive. This modified upwelled water then appears to move gradually offshore, sinking along the permanent pycnocline which slopes up to near the surface during upwelling. The modified upwelled water is warmer (but more saline), contains more scatterers than water of similar densities offshore, and thus appears as a thermal and optical inversion. The turbidity maximum was observed to persist after the temperature inversion disappeared, which would indicate that the circulation pattern remains even when insufficient heat is absorbed by the upwelled water to generate a thermal inversion.
Chapter 8 Archaean sedimentation on the Singhbhum Craton: depositional environments of conglomerates in Jharkhand (east India)

Abstract Archaean to Palaeoproterozoic metasediments overlie the Archaean granitoid pluton of the Singhbhum Craton in east India. Relatively little is known about the Archaean metasediments, but they comprise several conglomerates in the state of Jharkhand. Their age is most probably Mesoarchaean, possibly earliest Neoarchaean. They occur at separate localities and their exposures commonly consist of scattered patches with a limited extent. Their interrelationships are consequently poorly known. Sedimentological analysis of their structure, architecture and clast composition suggests that most of them represent individual occurrences that partly have been largely eroded away. Other occurrences must have had a limited extent from the very beginning. The various conglomerates were deposited in different environments. Some represent braided or meandering fluvial environments, whereas others seem to have been deposited by mass flows with different degrees of viscosity, possibly mainly on alluvial fans.
Impact-generated pseudotachylitic breccia in drill core BH-5 Hättberg, Siljan impact structure, Sweden

Pseudotachylitic breccia (PTB) in the form of cm-wide melt breccia veinlets locally occurs on the exposed central uplift of the 380 Ma Siljan impact structure. The host rock to the PTBs is the so-called Järna granite of quartz monzonitic to syenodioritic composition. The nearly 603 m long BH-5 drill core from Hättberg, near the centre of the Siljan central uplift, contains numerous veins and pods of PTB. In particular, two major zones of 60 m combined width contain extensive PTB network breccias (30% actual melt breccia component), with individual melt breccia occurrences up to >1 m in length. Core logging and petrographic and geochemical analysis of the core have been performed, and the data are interpreted to suggest the following. (1) The impact event caused low to moderate (at essentially < 20 GPa) shock deformation in the host rock and in clasts of this lithology within the PTB. (2) Macroscopic deformation of the basement mainly comprises fracturing, with only localised cataclasis. (3) No evidence for shock melting (i.e. compression/decompression melting early in the cratering process) could be observed. (4) Optical and scanning electron microscopy showed that dark PTB contains a definite melt component. (5) Shearing has significantly affected this part of the central uplift, but its effects are limited to very short displacements and likely did not result in extensive melting. (6) A frictional heating component upon melt generation can, however, not be excluded, as many PTB samples contain clasts of a mafic (gabbroic) component, although only in one place along the entire core, a 1.2 cm-wide section through such material in direct contact to host rock was observed. Consequently, we suggest that, upon uplift in the central part of the impact structure, considerable melt volumes were generated locally, especially in areas that had been affected by extensive cataclasis and where grain size comminution favoured melt formation. Rapid decompression related to central uplift formation is the preferred process for the generation of the PTB melt breccias.
Methodology for Developing Flood Rule Curves Conditioned on El Niño‐Southern Oscillation Classification 1

Lee, Se‐Yeun, Alan F. Hamlet, Carolyn J. Fitzgerald, and Stephen J. Burges, 2011. Methodology for Developing Flood Rule Curves Conditioned on El Niño‐Southern Oscillation Classification. Journal of the American Water Resources Association (JAWRA) 47(1):81‐92. DOI: 10.1111/j.1752‐1688.2010. 00490.x
Gas slug ascent through changes in conduit diameter: Laboratory insights into a volcano‐seismic source process in low‐viscosity magmas

Seismic signals generated during the flow and degassing of low-viscosity magmas include long-period (LP) and very-long-period (VLP) events, whose sources are often attributed to dynamic fluid processes within the conduit. We present the results of laboratory experiments designed to investigate whether the passage of a gas slug through regions of changing conduit diameter could act as a suitable source mechanism. A vertical, liquid-filled glass tube featuring a concentric diameter change was used to provide canonical insights into potentially deep or shallow seismic sources. As gas slugs ascend the tube, we observe systematic pressure changes varying with slug size, liquid depth, tube diameter, and liquid viscosity. Gas slugs undergoing an abrupt flow pattern change upon entering a section of significantly increased tube diameter induce a transient pressure decrease in and above the flare and an associated pressure increase below it, which stimulates acoustic and inertial resonant oscillations. When the liquid flow is not dominantly controlled by viscosity, net vertical forces on the apparatus are also detected. The net force is a function of the magnitude of the pressure transients generated and the tube geometry, which dictates where, and hence when, the traveling pressure pulses can couple into the tube. In contrast to interpretations of related volcano-seismic data, where a single downward force is assumed to result from an upward acceleration of the center of mass in the conduit, our experiments suggest that significant downward forces can result from the rapid deceleration of relatively small volumes of downward-moving liquid.
On the additivity of radiative forcing between land use change and greenhouse gases

In scientific and policy contexts, radiative forcing—an external change in Earth's mean radiative balance—has been suggested as a metric for evaluating the strength of climate perturbations resulting from different climate change drivers such as greenhouse gases and surface physical effects of land use change. However, the utility of this approach has been questioned given the spatially concentrated and sometimes nonradiative nature of land use climate disturbances. Here we show that when negative forcing from agricultural expansion is approximately balanced by a radiatively equivalent increase in atmospheric carbon dioxide, significant changes in temperature, precipitation, and the timing of climate change result. These idealized experiments demonstrate the nonadditivity of radiative forcing from land use change and greenhouse gases and point to the need for new climate change metrics or the development of climate policies and assessment protocols that do not rely on single dimensional metrics.
INTRODUCED EUCALYPTUS UROPHYLLA PLANTATIONS CHANGE THE COMPOSITION OF THE SOIL MICROBIAL COMMUNITY IN SUBTROPICAL CHINA

Fast‐growing tree species are widely used as pioneers for reforestation. These plantations strongly affect the ecosystem productivity and nutrient cycling, whereas their effect on the soil microbial community is still unclear. In a reforestation chronosequence in subtropical China consisting of Eucalyptus plantation with ages of 1, 2, 4 or 5 years, we examined the response of the soil microbial community and its function. The results showed that soil bulk density and dissolved organic carbon decreased significantly along the chronosequence. Soil pH was highest in the 5‐year‐old plantation. The amount of bacterial phospholipid fatty acids (PLFAs) and arbuscular mycorrhizal fungal PLFAs increased, but the ratio of fungal‐to‐bacterial PLFAs decreased with increasing forest age. The composition of the soil microbial community obviously changed after 5 years' development. Redundancy analysis showed that dissolved organic carbon was the major factor associated with the changes of soil microbial community composition. The short‐rotation Eucalyptus plantation could affect the composition of soil microbial communities through changing soil available carbon when planted in subtropical region at the early developmental stage. We suggest that soil microbial community composition should be taken into consideration in the large‐scale reforestation activities. Copyright © 2012 John Wiley & Sons, Ltd.
The palaeomagnetic evolution of continental red beds

Summary The palaeomagnetism of continental red beds is considered in the light of evidence concerning the diagenetic origin of various textural phases of hematite. The relative roles of pigmentary hematite and specularite as magnetization carriers is discussed and it is concluded that all magnetizations are post-depositional: the magnetization of continental red beds is therefore of diagenetic origin. Three types of non-viscous magnetization, A, B and C, are recognized in continental red beds. Type-A magnetizations retain some features of the original magnetization and are most closely coincident with the depositional age of the rocks. Type-B are composite magnetizations acquired over a long period (more than 108 yr) of time and after substantial changes in the ambient geomagnetic field. Type-C magnetizations bear no relationship to the depositional age of the rocks and represent the ultimate end-product of the diagenetic processes which affect continental red beds. Thus, these magnetizations represent stages in the diagenetic evolution of red beds. The rate of diagenetic evolution, and hence of the modification of the magnetization, is variable and depends on a variety of local geological variables. The study enables some assessment of the reliability of palaeomagnetic data from red beds. Type-A magnetizations, although of diagenetic origin, are considered to be palaeomagnetically reliable, but only within certain limits. Red beds with Type-B and Type-C magnetizations are not considered to be generally suitable for palaeomagnetic study. Palaeomagnetic studies are, however, considered to have great potential value for dating specific diagenetic processes in continental red beds.
MEASURING THE INTERNET: HOST COUNTS VERSUS BUSINESS PLANS

The excessive media attention in and economic hopes placed on the Internet mean that measures of its size and distribution have been undertaken more often with an eye to business plans than to methodological rigour.This paper examines one disinterested source of Internet statistics, the Internet Domain Survey, to provide accurate measures of Internet size and distribution. Methodological issues in utilizing this survey are discussed to ensure the significance of findings is understood and to identify key methodological problems in a new field of research. Two particular problems are identified; the need to define user per computer host ratios and to identify the national origin of computers with international domain names. Statistics are presented from the five Internet Domain Surveys from January 1998 to January 2000 in the following categories: overall size, regional distribution, human development and economic distribution, linguistic distribution and user numbers. The conclusion is reached that even as the Internet is growing in all regions world-wide it remains concentrated in the highly developed nations. Some consideration of the implications of this for wider debates around the Internet is given.
Oxidation degree of chromite from Indian ophiolites: a crystal chemical and 57Fe Mössbauer study

Several samples of Cr-bearing spinel from Indian ophiolites have been studied by X-ray single crystal diffraction and structure refinement, electron probe microanalyses and Mossbauer spectroscopy. Differences between samples coming from massive chromitite bands and those coming from podiform chromitite deposits have been evidenced: the former have (Mg,Fe)-chromite component ≥ 75%, the latter from 69 to 74%. In both cases the complementary components are aluminate (mainly spinel sensu stricto MgAl 2O4). As magnesiochromite (MgCr 2O4) is always dominant with respect to chromite (FeCr 2O4), the studied samples are classified as magnesiochromite. The multi-analytical approach has revealed that some of the studied spinels are non-stoichiometric (due to Fe 2+ oxidation and vacancy formation), with those coming from massive chromitite being more oxidised than those from the pods. Comparison between our results and recent literature suggested that spinel oxidation is more common than usually believed: it is not restricted to ophiolites but may occur in different geological settings and may help reconstructing the complex thermooxidative history of the host rock. Consequently, the proposed multi-analytical approach is crucial for an accurate crystal chemical characterisation of spinels and other Fe-bearing mineral phases, especially when geothermobarometric calculations have to be performed.
Uncertain Futures - Adaptive capacities to climate variability and change in the Lake Victoria Basin

The Lake Victoria basin (LVB) in East Africa can be considered a climate change hotspot because of its large rural population dependent on rain-fed farming. Drawing on extensive fieldwork (2007-2011) in rural communities along the shores of Lake Victoria in Kenya and Tanzania, I explore adaptive capacities to climate variability and change and discuss how they interrelate in situ. Using multiple methods, tools and techniques, including survey and rainfall data, individual and group interviews, interactive mapping of seasonal calendars and a multi-stakeholder workshop, I locate the place-based effects and responses to a number of converging climate induced stressors on smallholder farmers’ wellbeing and natural resources. Research findings show that adaptive capacities to climate variability and change in the LVB are complex, dynamic and characterized by high location-specificity, thereby signifying the value of using an integrative and place-based approach to understand climate vulnerability. Specifically, the study demonstrates how increased unpredictability in rainfall causes chronic livelihood stress illustrated by recurring and worsening periods of food insecurity, growing cash dependency and heavy disease burdens. The study also reveals that food and income buffers increase when and where farmers, particularly women farmers, collectively respond to climate induced stressors through deliberate strategies rooted in a culture of saving and planning. Nevertheless, the study concludes that smallholders in the LVB are facing a highly uncertain future with discernible, yet differentiated adaptation deficits, due to chronic livelihood stress driven by unequal access to fundamental adaptive capacities such as land, health, cash and collective networks. (Less)
Self-consistent rolling-hinge model for the evolution of large-offset low-angle normal faults

The nature of the physical processes responsible for the formation of continental and oceanic metamorphic core complexes is widely debated. The controversy focuses primarily on whether the low-angle normal faults observed in these environments formed and slipped at low angles or were rotated from an original high-angle orientation after large offsets. We describe a self-consistent numerical model for the extension of a brittle layer that can spontaneously produce normal-fault structures. In our formulation, a fault or faults form because strength is locally reduced with increasing strain. If the reduction in fault strength is <∼10% of the total strength of the layer, then faults lock after an offset smaller than the layer thickness and new faults form. Larger strength reduction leads to single faults that continue to slip no matter how large the fault offset. If the strength reduction occurs by the loss of cohesion, then we see the unlimited offset faults for layers <11–22 km thick for reasonable values of cohesion. The key result of this study is that structures very similar to those observed in both oceanic and continental core complexes are produced by rotation of the inactive part of the model fault after very large offset.
Winter water masses in the Gulf of St. Lawrence

[1] The first 9 years of data collected during a new late wintertime hydrographic survey of the Gulf of St. Lawrence are presented. They show colder conditions than those previously measured from ships that were likely biased toward warmer ice-free waters. The total volume of cold water (<−1°C) varied interannually from 10 to 15 × 103 km3 and is a good predictor for the following summertime Cold Intermediate Layer index. The volume of cold and saline Labrador Shelf waters that flowed in through the Strait of Belle Isle is estimated using two temperature-salinity criteria. It exhibits much stronger interannual variability than the total cold water volume, representing from 5% to as much as 30% of all cold surface waters. It was sometimes observed to reach the bottom in Mecatina Trough at more than 200 m depth, where deep waters are isolated from the rest of the gulf.