Miracle-dz/UniFAR-FTUs huggingface dataset:
A Model Study of Heat Waves over North America: Meteorological Aspects and Projections for the Twenty-First Century

AbstractThe characteristics of summertime heat waves in North America are examined using reanalysis data and simulations by two general circulation models with horizontal resolution of 50 and 200 km. Several “key regions” with spatially coherent and high amplitude fluctuations in daily surface air temperature are identified. The typical synoptic features accompanying warm episodes in these regions are described. The averaged intensity, duration, and frequency of occurrence of the heat waves in various key regions, as simulated in the two models for twentieth-century climate, are in general agreement with the results based on reanalysis data.The impact of climate change on the heat wave characteristics in various key regions is assessed by contrasting model runs based on a scenario for the twenty-first century with those for the twentieth century. Both models indicate considerable increases in the duration and frequency of heat wave episodes, and in number of heat wave days per year, during the twenty-firs.
Relationship between self‐potential (SP) signals and redox conditions in contaminated groundwater

In situ measurements of redox potential are rather difficult to perform and provide only sparse information on its spatial distribution. To delineate redox fronts in a contaminant plume, the self‐potential (SP) method can be a helpful complement to geochemical measurements. Here, we apply the SP method to the Entressen municipal waste landfill (south‐eastern France) over a 20 km2 area. The results show a large negative SP‐anomaly of ∼−400 mV with respect to a reference station taken outside the contaminant plume. Once removed the electrokinetic component associated with groundwater flow, the residual self‐potential signals are linearly correlated with in situ measurements of redox potential. We propose a quantitative relationship between self‐potential and redox potential, which would be used to invert self‐potential measurements in terms of in situ redox potential values in contaminant plumes.
June‐september rainfall in north‐eastern Africa and atmospheric signals over the tropics: A zonal perspective

The connection between rainfall in northeast Africa (Djibouti, Eritrea, Ethiopia, Kenya, Somalia, Sudan, and Uganda) and various atmospheric indicators from the tropics have been investigated for the northern summer season. Variables used include zonal wind at 700 hPa and 200 hPa, sea-level pressure, and rainfall over other tropical areas, for the period 1951–1988. Strong significant correlations are shown with the Southern Oscillation and the components of the Walker cell in the Pacific Ocean. Droughts in the Ethiopia-Uganda area are associated with El Nino events and, moreover, with above normal pressure and droughts over India. Other significant relationships exist with the African monsoon. Westerly (easterly) anomalies in the lower (upper) levels are associated with abundant summer rainfall years in north-east Africa. These results are all consistent with the previously defined Walker-type circulations over the tropics, particularly as far as the Indo-Pacific and African cells are concerned. Although the Southern Oscillation has a dominant impact in this respect, the specific coherence of the African cell is further evidenced. Preliminary findings suggest that the summer rainfall areas of East Africa could qualify as a location for the rising branch of this cell.
How to run a minimalist's global ocean conveyor

The current paradigm of modern climatology and oceanography is that the thermohaline ocean circulation comprises a so‐called global ocean “salinity conveyor belt” – a system of currents connecting the northern North Atlantic and northern North Pacific. A hypothesis is put forth here that a slight disparity in freshwater redistribution between the oceans in the Northern Hemisphere is sufficient to build up and maintain a global conveyor‐type ocean thermohaline circulation.
Mineralogy of Saharan dust transported over northwestern tropical Atlantic Ocean in relation to source regions

[1] On the basis of daily Saharan dust samples collected at Sal Island (Cape Verde Archipelagos) and Barbados (Caribbean Sea) over 3 years, this study focuses on the mineralogical signature of the African sources providing dust over the tropical North Atlantic Ocean. First, the sources of the collected dust were localized by using relative clays abundance (illite-to-kaolinite ratio) combined with Meteosat infrared imagery, horizontal visibility, and backward trajectories of dusty air masses. Then, each identified source was linked to a single value of the illite-to-kaolinite ratio. Those results highlight that the clay content of the emitted dust depends directly on both the latitude and the longitude of the source. Dust originating from northwestern sources exhibits illite-to-kaolinite ratios higher than those from Sahelian regions. Likewise, illite-to-kolinite ratio decreases from west to east.
Petrology and geochemistry of the Andaman ophiolite: melt–rock interaction in a suprasubduction-zone setting

Abstract: The Andaman ophiolite occurs as thrust slices in the outer arc of the Andaman–Java subduction zone. This ophiolite preserves the mantle sequence, layered ultramafic–mafic rocks, intrusive and extrusive rocks. The mantle sequence is represented by serpentinized lherzolite and harzburgite, hosting dunite and chromitite pods. The low Cr-number (0.2–0.4), Cr-number–TiO2 relation of the chromites, oxygen fugacity (fO2) values (Δlog fO2 (FMQ) = −1.90) and trace elements of mantle peridotites indicate a mid-ocean ridge basalt–suprasubduction-zone (MORB–SSZ) setting. The MORB mantle underwent a low degree of melting (c. 10–15%) and interacted with the subduction-zone melts. Melt–rock interaction of the peridotites in a suprasubduction zone is demonstrated by the replacement of pyroxene grains by olivine grains (Fo90), composition of chromites and oxygen fugacity (Δlog fO2 (FMQ) = –1.90 to +2.16, where FMQ is the fayalite–magnetite–quartz buffer). The chromite composition of chromitite pods (Cr-number 0.72–0.75), fO2 levels and trace elements for layered peridotites, and occurrence of the extrusive rocks as low-Ca boninite and island arc tholeiitic (IAT) basalt indicate interplay of both boninite and IAT melts for the Andaman ophiolite. The MORB mantle of the subducting Indian plate accreted into the mantle wedge and then melting of the accreted mantle produced boninite melt at the first stage and tholeiitic melts at the second stage. Supplementary material: Sample co-ordinates from the Andaman ophiolite, mineral analysis data for all the samples, modal compositions of the units of the Andaman ophiolite and details of the laboratory analyses including details of the standard are available at http://www.geolsoc. org.uk/SUP18459.
Chromatin remodeling by the small RNA machinery in mammalian cells

Chromatin states, quite different from changes in DNA sequence, can impact fundamental cellular processes such as determination of cell identity and development of disease. However, how chromatin states are established and regulated remain to be fully elucidated. In several lower eukaryotes, the small RNA machinery comprised of small RNA and its partners, the Argonaute proteins, is known to play important roles in the establishment of heterochromatin and silencing of repetitive sequences. In mammalian cells, however, the nuclear function of the small RNA machinery is largely unknown. Emerging evidence suggests that components of the small RNA pathway interact with chromatin to regulate nuclear events, including gene transcription and alternative splicing. In addition, these endogenous mechanisms are being exploited to target specific genomic loci for manipulation of gene expression and splicing events. In this review, I summarize current understanding of chromatin remodeling by small RNAs in mammalian cells and highlight recent efforts to map genome-wide interactions between RNAi-related factors and chromatin.
Flood management and a GIS modelling method to assess flood-hazard areas—a case study

Abstract This paper presents a viable approach for flood management strategy in a river basin based on the European Floods Directive. A reliable flood management plan has two components: (a) a proper flood management strategy, and (b) the determination of the flood-hazard areas. A method to evaluate the benefits of a flood warning system is presented herein, as well as a method to estimate the flood-hazard areas. Six factors were considered in order to estimate the spatial distribution of the hazardous areas: flow accumulation, slope, land use, rainfall intensity, geology and elevation. The study area was divided into five regions characterized by different degrees of flood hazard ranging from very low to very high. The produced map of flood-hazard areas identifies the areas and settlements at high risk of flooding. The proposed methodology can be applied to any river basin and here was applied to the Koiliaris River basin in Greece. Citation Kourgialas, N. N. & Karatzas, G. P. (2011) Flood management and a GIS modelling method to assess flood-hazard areas—a case study. Hydrol. Sci. J. 56(2), 212–225.
Introduction to special section: Outstanding problems in quantifying the radiative impacts of mineral dust

This paper provides an introduction to the special section of the Journal of Geophysical Research on mineral dust. We briefly review the current experimental and theoretical approaches used to quantify the dust radiative impacts, highlight the outstanding issues, and discuss possible strategies to overcome the emerging problems. We also introduce the contributing papers of this special section. Despite the recent notable advances in dust studies, we demonstrate that the radiative effects of dust remain poorly quantified due to both limited data and incomplete understanding of relative physical and chemical processes. The foremost needs are (1) to quantify the spatial and temporal variations of dust burden in the atmosphere and develop a predictive capability for the size- and composition-resolved dust particle distribution; (2) to develop a quantitative description of the processes that control the spatial and temporal variabilities of dust physical and chemical properties and radiative effects; (3) to develop new instrumentation (especially to measure the dust particle size distribution in a wide range from about 0.01 μm to 100 μm, scattering phase function and light absorption by dust particles); and (4) to develop new techniques for interpreting and merging the diverse information from satellite remote sensing, in situ and ground-based measurements, laboratory studies, and model simulations. Because dust distribution and effects are heterogeneous, both spatially and temporally, a promising strategy to advance our knowledge is to perform comprehensive studies at the targeted regions affected by mineral dust of both natural and anthropogenic origin.
Modification of clast shape in high-Arctic glacial environments

ABSTRACT Clast shape data from a range of different glacial environments at several high-arctic valley glaciers in Svalbard are presented. These data add to the growing body of reference information about clast shape in modern glacial environments and is used to explore the role of lithology in clast morphogenesis and to evaluate the different methodological approaches to the analysis of clast shape data. The following conclusions are drawn: (1) it is possible to distinguish clasts transported subglacially from those moved supraglacially; (2) it is not possible to differentiate among different types of subglacial sediment or to distinguish them collectively from glaciofluvial samples; (3) lithology has some influence on clast shape, although not as much as previously suggested; and (4) covaria t plots of the RA (percentage of angular and very angular clasts) versus C40 (percentage of clasts with c to a axial ratio <=0.4) index give superior data visualization and discriminate more effectively among different glacial sediments than sphericity and roundness plots.
Growth Patterns of Deep-Sea Fans

The growth pattern of a deep-sea fan relates events in and around the fan-valleys to the structure and morphology of the open fan. The growth pattern cannot be determined without knowledge of the origin and recent history of the fan-valley system. The mapping of La Jolla and San Lucas deep-sea fans with the deep-towed instrument package developed at Marine Physical Laboratory of the Scripps Institution of Oceanography details the fine-scale morphology, structure, and internal fill of the fan-valleys and suggests the growth patterns of these fans. The La Jolla fan, 20 km west of Scripps Institution, has one meandering fan-valley that extends across the entire fan. Except on the toe of the fan, the deeply incised valley has terraced walls with steeper walls on the outside of meanders. Very low-relief levees border the fan-valley in some localities. The present erosional valley bypasses the partly buried remnants of an older distributary system on the lower fan. The San Lucas fan, off the southern tip of the peninsula of Baja California, shows a depositional lobe of sediment, or suprafan, below the short, leveed fan-valley extending from San Jose Canyon. The suprafan appears as a convex-upward bulge on a radial profile of the fan. The surface of the suprafan has a series of discontinuous depressions up to 55 m deep and 1 km wide. The depressions are generally asymmetric in cross section, commonly have terraced walls, and are underlain by coarse sand and gravel. They are interpreted to be channel remnants. A model for deep-sea fan growth, based on this study, predicts that deposition on a fan will be localized in a suprafan at the end of large, leveed valleys commonly found on, and generally confined to, the upper reaches of deep-sea fans. The suprafan normally is on the midfan and is characterized by numerous smaller distributary channels. Rapid aggradation in the suprafan coupled with migration and meandering of the channels produces a surface marked by isolated depressions or channel remnants. Uniform deposition, producing a symmetrical half-cone morphology, results from the shifting through time of fan-valleys across the area of the fan.
Low-frequency bursts of horizontally polarized waves in the Arctic sea-ice cover

Abstract We report the detection of bursts of low-frequency waves, typically f = 0.025 Hz, on horizontal channels of broadband seismometers deployed on the Arctic sea-ice cover during the DAMOCLES (Developing Arctic Modeling and Observing Capabilities for Long-term Environmental Studies) experiment in spring 2007. These bursts have amplitudes well above the ambient ice swell and a lower frequency content. Their typical duration is of the order of minutes. They occur at irregular times, with periods of relative quietness alternating with periods of strong activity. A significant correlation between the rate of burst occurrences and the ice-cover deformation at the ∼400 km scale centered on the seismic network suggests that these bursts are caused by remote, episodic deformation involving shearing across regional-scale leads. This observation opens the possibility of complementing satellite measurements of ice-cover deformation, by providing a much more precise temporal sampling, hence a better characterization of the processes involved during these deformation events.
Changes in Aggregate Stability and Concentration of Glomalin during Tillage Management Transition

Improvement in structure of degraded soils or prevention of degradation of structure in healthy soils requires an understanding of processes contributing to aggregate stability. The impact of cropping systems on a specific molecule that contributes to aggregate stability is part of the process that has not been elucidated. The relationship between aggregate stability and glomalin, a glycoprotein produced by arbuscular mycorrhizal (AM) fungi, was studied during the first 3 yr in transition from plow tillage (PT) to no tillage (NT) maize (Zea mays L.). Results showed a high linear correlation (r 2 = 0.78, n = 32) between glomalin concentration in aggregates and aggregate stability. Increases in both aggregate stability and glomalin were measurable from year to year in NT plots, but NT was significantly higher than PT after 2 or 3 yr (P < 0.05). Comparison of NT plots after 3 yr with nearby soil in grass cover indicated that there was 20% greater stability and 45% higher concentration of glomalin in the grass-covered soil. Comparison of PT and NT (3 yr) interrow samples with intrarow samples indicated that plant roots and NT management may have a synergistic effect on aggregate stabilization. These results show that cropping systems should be evaluated for the impact on production of glomalin by AM fungi.
The high‐latitude winter F region at 300 km: Thermal plasma observations from AE‐C

Ion composition and electron temperature data obtained from AE-C during a magnetically quiet period centered on the June 1976 solstice have been used in a statistical study of the southern winter F region poleward of -50° Λ at 300-km altitude. Prominent ionospheric features revealed by topographic maps of O+, NO+, and O2+ concentration and Te include the nightside main trough, an ionization ‘hole’ poleward of the nightside auroral zone, and ionization and Te enhancements in the dayside auroral zone-cusp region. The main trough, in which O+ was the dominant ion, extended throughout the night between -60° and -70° Λ, the lowest trough densities, ∼1 × 10³ cm−3, being detected near dusk. We attribute these low concentrations to the opposition, in the dusk sector, of plasma corotation and solar wind induced plasma convection velocities, leading to long plasma residence (and decay) times. That the distributions of NO+ and O2+ in the trough region exhibited little correlation with O+ suggests that drift-enhanced O+ loss via reactions such as O+ + N2 → NO+ + N played a minor role in the formation of the trough during this period. A band of enhanced electron temperature coincided with the trough throughout the night; this Te peak, which has been observed previously in the topside ionosphere, is attributed to heat conducted downward from the protonosphere. The ionization hole, a region poleward of the nightside auroral zone between -70° and -80° Λ, was characterized by depletions in all the measured ion densities and by a minimum in Te. The total ion concentration measured in this region exhibited extreme temporal variability, ranging from values as low as 2 × 10² to 6 × 10³ cm−3. We have concluded that the hole forms as a result of slow antisunward plasma drift across the dark polar cap and attendant ion recombination; an average drift velocity of ∼0.1 km/s, corresponding to a convection electric field of less than 5 mV/m, could produce the deepest holes observed. The ion density variability in the hole is attributed to changes in the transpolar plasma convection configuration and the distribution of energetic particle fluxes. The dayside auroral zone-cusp region was characterized, in general, by enhanced levels of ionization and electron temperature associated with energetic particle precipitation. On some passes through this region, however, localized O+ depletions and corresponding molecular ion increases were detected; we attribute these features to the reactions O+ + N2 → NO+ + N and O+ + O2 → O2+ + O, whose rates are enhanced by the high-speed plasma drifts observed in the cusp region.
Petrology of the Kurancali Phlogopitic Metagabbro: An Island Arc-Type Ophiolitic Sliver in the Central Anatolian Crystalline Complex

The Kurancali metagabbro occurs as an isolated body in the central part of the Central Anatolian Crystalline Complex. It has been emplaced along a steep S-vergent thrust-plane onto the uppermost units of the Central Anatolian Metamorphics. The main body of the Kurancali metagabbro is characterized by distinct compositional layering. The layered gabbros comprise pyroxene and hornblende gabbros. Phlogopite-rich, plagioclase-hornblende gabbro occurs mainly as pegmatitic dikes intruding the layered gabbro sequence. The layered gabbros, in general, consist mainly of diopsidic augites, brown hornblendes, and plagioclase. Secondary phases are phlogopitic mica, brownish-green hornblende replacing clinopyroxenes, and fibrous, greenish actinolitic hornblende partially or completely replacing brown hornblende. The primary dark micas are phlogopitic in the range of phlogopite(57-70) and annite(30-43). The analyzed pyroxenes are diopsidic (En32Fs19Wo49-En35Fs18Wo48). The whole-rock geochemistry of the gabbros indicates the presence of two distinct groups of rocks; a less pronounced group of phlogopite gabbro with island-arc calc-alkaline affinities, and a dominating layered gabbro sequence with island-arc tholeiite characteristics. They are extremely enriched in LILE, indicative of alkaline metasomatism in the source region, and display geochemical features of transitional backarc-basin basalts (BABB)/island-arc basalts (IAB)—and IAB-type oceanic crust. Based on their geochemical similarities to modern island-arc basements, we suggest that the Kurancali metagabbro may represent the basement of an initial island arc, generated in a suprasubduction zone setting within the Izmir-Ankara branch of Neotethys.
Analysis of the linear response function relating AL to VBs for individual substorms

Time series of the AL index and rectified solar wind electric field are used to study solar wind coupling to auroral ionospheric currents during individual substorms. Calculation of the individual filters is accompanied by representing them as the product of two simple filters: a low-pass filter that accounts for the response of the ionospheric electric field to the reconnection electric field, and a filter composed of delta function. The delta functions each have the effect of delaying and scaling the response of AL relative to VB{sub s} without distorting the waveform of VB{sub s}. Nearly all significant correlation between AL and VB{sub s} can be accounted for when the second filter contains only two components. This result suggests that the westward electrojet indexed by AL is controlled by two distinct processes, both proportional to VB{sub s}. For an ensemble of 117 isolated substorms the average prediction efficiency of a filter with two delays is 71%. If one were able to determine the exact values of the two delays and the two gain factors prior to an event, then one would be able to estimate the instantaneous magnetospheric response function. The authors examined season, universal time, and prior activity as possiblemore » factors controlling the magnitude of the parameters but found no apparent relationships. Until such relations are found the average parameters provide the best estimate but account for only 47% of the variance in the AL index. 20 refs., 10 figs.« less
Roman Ruins as an Experiment for Radiocarbon Dating of Mortar

The remains of Vindonissa, the Roman legionary camp in Switzerland, have been the subject of extensive archaeological studies. Knowledge of the building time plays a role in reconstructions of the history of this site. We radiocarbon dated mortar samples selected from one of the Roman monuments (Westtor) as well as a nearby Medieval monastery. 14C ages obtained on the first fraction and second fraction of very short dissolution appear close to the expected Roman age of ∼2000 BP, while the monastery is dated to historic times, after AD 1308.