Miracle-dz/UniFAR-FTUs huggingface dataset:
A geometrical approach to the elastic complex screen

The elastic complex screen, or “phase screen” approach to the forward modeling of elastic waves promises significant advantages over other computational schemes, because it is potentially much less intensive numerically than finite difference methods, and yet it models essentially the whole useful wave field. In this paper it is shown how the equations that describe the technique can be derived through a geometrical construction. The new formulation is presented in conjunction with an overview of the earlier derivation of Wu [1994] in order to emphasize the similarities and differences between the two approaches. The geometrical derivation provides for a formulation in terms of interfaces (steps) rather than slabs. It also leads quite naturally to the incorporation of backscattered energy in the model. An algorithm to implement this important capability is developed in some detail and includes a backpropagation technique, which improves storage efficiency by removing the need to store the backscattered field at each screen independently. Numerical results are presented for some simple backscattering models, first of all to validate the theory, but then more specifically to illustrate the frequency response of the model and the implications it has for the choice of a suitable source spectrum.
Nonhydrostatic climate simulations of precipitation over complex terrain

A climate version of the nonhydrostatic fifth-generation Penn State/NCAR Mesoscale Model has been used to downscale a global climate scenario to cloud-resolving scales over complex terrain (the Alps). After first describing the model and methodology, we then present comparison results from the model-predicted and ensemble-averaged regional-scale winter and summer season precipitation distribution with results from the global simulation and analyzed observed precipitation climatologies. Finally, results from the cloud-resolving simulations are compared to the regional simulations. It is shown that the degree to which the terrain is resolved in the various runs significantly alters the simulation of the precipitation climatologies. This is caused not only by the complex interaction of the flow with the topography but also by the different treatment of the convective processes (resolved versus nonresolved) in the model. Even in winter, the model-simulated seasonally averaged precipitation patterns change drastically with every increase in horizontal resolution. Furthermore, with a horizontal grid resolution of 1 km, when seen on a local scale and over complex terrain, the model-simulated precipitation patterns are not guaranteed to converge to one solution. This behavior is still more complicated in summer. Here it is shown that parameterized convection in the regional model simulation tends to be locked to the mountains, while in the cloud-resolving simulations the convection moves with the upper level flow, producing precipitation maxima away from the mountain tops.
The Intricacies of Children’s Physical Activity

Abstract Understanding the physical activity patterns of youth is an essential step in preparing programming and interventions needed to change behavior. To date, little is known about the intricacies of youth physical activity across various physical activity segments (i.e. in school, out of school, recess, classroom physical activity, physical education, weekends, etc.). Therefore, the purpose of the study was to examine the physical activity patterns of elementary school children across various segments and during two seasons. A total of 287 fourth and fifth graders from the Southwest US wore the Yamax Digiwalker SW-200 pedometer for 7 consecutive days during the Fall and Spring seasons. Children were prompted to record their step counts when arriving and leaving school, before and after physical education and recess, as well as on the weekends. Means and standard deviations were calculated and ANOVAs and t tests were utilized to examine difference by sex, season, and segment. Youth were more active outside of school and on weekdays (p<0.05). Boys were generally more active than girls and all youth were more active during the milder Spring season. There is a clear need for Comprehensive School Physical Activity Programming and weekend physical activity opportunities. Furthermore, greater emphasis is needed on PE and across other activity segments for girls to increase their physical activity levels.
The Chronotype of Elite Athletes

Abstract The aims of this study were (i) to compare the chronotype distribution of elite athletes to a young adult population and (ii) to determine if there was a tendency for athletes to select and/or participate in sports which suited their chronotype. A total of 114 elite athletes from five sports (cricket, cycling, hockey, soccer and triathlon) participated in this study. The participants’ chronotype, sleepiness, sleep satisfaction and sleep quality were determined using the Horne and Östberg Morningness and Eveningness questionnaire, the Epworth Sleepiness Scale and questions concerning their sleep satisfaction and quality. All questionnaires were administered during a typical training phase that was not in the lead up to competition and/or post competition. No differences between chronotype group for sleepiness, sleep satisfaction or sleep quality were found. There was a significantly higher proportion of triathletes that were morning and intermediate types compared to the control group χ2 (2) = 7.5, p = 0.02. A significant relationship between sport and chronotype group (χ2(4)=15.9, p = 0.04) was observed, with a higher frequency of morning types involved in sports that required morning training. There was a clear indication that athletes tended to select and pursue sports that suited their chronotype. This was evident by the amount of morning types involved in morning sports. Given that athletes are more likely to pursue and excel in sports which suit their chronotype, it is recommended that coaches consider the athlete’s chronotype during selection processes or if possible design and implement changes to training schedules to either suit the athletes’ chronotype or the timing of an upcoming competition.
Elastic modelling in tilted transversely isotropic media with convolutional perfectly matched layer boundary conditions

To simulate wave propagation in a tilted transversely isotropic (TTI) medium with a tilting symmetry-axis of anisotropy, we develop a 2D elastic forward modelling algorithm. In this algorithm, we use the staggered-grid finite-difference method which has fourth-order accuracy in space and second-order accuracy in time. Since velocity-stress formulations are defined for staggered grids, we include auxiliary grid points in the z-direction to meet the free surface boundary conditions for shear stress. Through comparisons of displacements obtained from our algorithm, not only with analytical solutions but also with finite element solutions, we are able to validate that the free surface conditions operate appropriately and elastic waves propagate correctly. In order to handle the artificial boundary reflections efficiently, we also implement convolutional perfectly matched layer (CPML) absorbing boundaries in our algorithm. The CPML sufficiently attenuates energy at the grazing incidence by modifying the damping profile of the PML boundary. Numerical experiments indicate that the algorithm accurately expresses elastic wave propagation in the TTI medium. At the free surface, the numerical results show good agreement with analytical solutions not only for body waves but also for the Rayleigh wave which has strong amplitude along the surface. In addition, we demonstrate the efficiency of CPML for a homogeneous TI medium and a dipping layered model. Only using 10 grid points to the CPML regions, the artificial reflections are successfully suppressed and the energy of the boundary reflection back into the effective modelling area is significantly decayed. In this study, we developed a forward modelling algorithm with the staggered-grid finite-difference method. The elastic wave propagation in 2D tilted transversely isotropic media is well simulated using this algorithm. We also implement convolutional perfectly matched layer absorbing boundaries in our algorithm in order to handle the artificial boundary reflection efficiently.
On the potential of MODIS and MERIS for imaging chlorophyll fluorescence from space

The first images from MODIS (Moderate Resolution Imaging Spectroradiometer) are now being used to evaluate information on the in vivo fluorescence peak near 685 nm from chlorophyll-a, stimulated by sunlight. The Fluorescence Line Imager (FLI) airborne imaging spectrometer was used in the 1980s to demonstrate the mapping of this signal from an aircraft, showing that it gave significant rejection of confusing signals from atmospheric radiance. For imaging from space, a major limitation is sensor sensitivity, which tends to restrict imaging to relatively high concentrations under good solar illumination. Noise-equivalent chlorophyll concentrations for MODIS and MERIS (Medium Resolution Imaging Spectrometer) have been estimated as 0.07 and 0.1 mg m−3, respectively, under zenith Sun, clear sky conditions. Although MERIS has slightly poorer sensitivity, it has the advantage of flexible band placing and presence of a band at 709 nm in the baseline band-set that allows better definition of the continuum spectrum above which fluorescence is measured. This band should also allow detection of bright plankton blooms (red-tide events) through the peak radiance near 709 nm caused by a combination of in-water scattering and absorption.
Transient Hydrogeological Controls on the Chemistry of a Seepage Lake

A solute mass balance method was used to estimate groundwater inflow and outflow rates for Nevins Lake, Michigan, a seepage lake in the upper peninsula that historically has shown extremely variable water chemistry compared with most other seepage lakes. A 4-year study (1989–1992) of the hydrology and geochemistry of Nevins Lake and its contiguous groundwater system revealed that changes in the mass of dissolved solutes are the result of annual hydraulic gradient reversals. A pronounced acidification of Nevins Lake from 1986 to 1988 was likely caused by drought-induced diminished groundwater inflow rates. In this study, dissolved calcium (the major cation in water of Nevins Lake, groundwater, and precipitation) was used for estimating mass flow rates. During the 1989–1992 period, Nevins Lake showed a reproducible annual cycle in calcium mass. Immediately following spring snowmelt and the resulting hydraulic gradient reversal, the mass of dissolved calcium in the lake increases rapidly, and then it decreases steadily throughout the summer and early fall, at which time the lake becomes hydraulically mounded and receives no groundwater inflow. Groundwater flow rates estimated by the solute mass balance method are sensitive to assumed solute concentrations in discharging groundwater. Pore water samples from the lake bed are shown to be more representative of water discharging to the lake than are samples from piezometers near the lake shore, but spatial and temporal variability in pore water chemistry must be considered. Stable isotope analyses (18O and 2H) of lake water, groundwater, and pore water samples show that water discharging to Nevins Lake in the spring is entirely recycled lake water, and no groundwater derived from terrestrial recharge reaches the lake. The conceptual model formulated during this study linking lake chemistry and the contiguous groundwater system and general groundwater flow patterns surrounding highly transient lake systems are likely transferable to other similar systems.
Regional Wavefield reconstruction for teleseismic P‐waves and Surface waves

With the recent availability of dense seismological array data there is the opportunity to reconstruct 2D wavefields of propagating seismic energy. Such a reconstruction allows seismic data to be viewed as wavefields rather than as single station traces. Reconstruction of such wavefields within an array will improve our understanding of complex wave propagation effects and, hence, the underlying Earth structure beneath the array. We propose an algorithm applicable for teleseismic waves that is based on wavefield expansion by cubic B‐splines. Application to the high‐density array in Southern California shows that we can identify basin resonances and wavefront shifts; such wavefield shifts could be caused by local structure or travel path structure, as waves pass through major structural contrasts.
The Neogene to Recent Rallier-du-Baty nested ring complex, Kerguelen Archipelago (TAAF, Indian Ocean): stratigraphy revisited, implications for cauldron subsidence mechanisms

Abstract The Kerguelen Archipelago is made up of a stack of thick piles of Tertiary flood basalts intruded by transitional to alkaline igneous centres at various times since 30 Ma ago. In the SW, the Rallier-du-Baty Peninsula is mostly occupied by two silicic ring complexes, each with an average diameter of 15 km, comprising dissected calderas cross-cut by subvolcanic cupolas. Previous radiometric determinations yield ages ranging from 15.4 to 7.4 Ma in the southern centre, and 6.2 to 4.9 Ma in the northern one. The felsic ring dykes were injected by coeval mafic magmas, forming, successively, swarms of early mafic enclaves, disrupted synplutonic cone sheets, and late cone-sheets. After the emplacement and subsequent unroofing of the plutonic ring complexes, abundant and thick trachytic pyroclastic flows and falls were emitted from the younger caldera volcanoes, while hawaiite and mugearite lava flows were erupted from marginal maars and cones. Huge trachyte ignimbritic flows filled the glacial valleys in the central Peninsula, and capped lacustrine deposits and older lava flows, while related pumice falls are widespread throughout the archipelago. This powerful plinian eruption took place after the network of glacial valleys was established, but before the Little Ice Age that occurred during the last centuries. In the south of the peninsula, even younger trachytic formations are exposed, and fumarolic vents are still active. The growth mechanisms of a caldera-related ring complex can be explained as a repetitive sequence of two eruptive episodes. The first episode of hydrofracturing, induced by volatile exsolution within the evolving magma chamber, creates a vertical circular fracture zone, along which highly vesiculated magmas are emitted during explosive eruptive events occurring at the surface in a caldera volcano. It is followed by a second episode of cauldron-subsidence of a crustal block down to the degassed magma chamber, induced by pressure release. Downward movement of the crustal block favours the emplacement at shallow depths within the older caldera-filling formations, of discrete magmatic sheets characterized by a 16-km mean diameter and a 1-km mean thickness, corresponding to an average unit volume of 200 km3. Actually, the estimated volumes of the different igneous episodes within the Rallier-du-Baty nested ring complex vary from 60 to 900 km3, and correspond to the production during 15 Ma of about 2800 ± 850 km3 of new materials and a net crustal growth of about 100 ± 30 × 103 m3 per year.
L'assimilation opérationnelle de données régionales à Météo-France

EnglishThe regional limited area model Aladin/France has been run since July 2005 with its own data assimilation cycle. Before, the initial conditions for Aladin/France were taken from Arpege data, interpolated from a global to a plane projection grid. This change has been accompanied by the use, in the Aladin analysis, of observational data not assimilated in Arpege: radiances obtained by the Seviri instrument onboard Meteosat-8, and the temperature and relative humidity at 2 m. One noticeable impact of this change is an improvement in the shortrange forecast of precipitations, both in a statistical sense (scores over 1.5 month) and in real cases of early summer convection. Future developments of the system include the use of new observations and the adaptation of the variational analysis to very high resolution for the Arome system. francaisLe modele regional a aire limitee Aladin/France possede depuis juillet 2005 son propre cycle d'assimilation de donnees. Auparavant, Aladin /France prenait ses conditions initiales du modele global Arpege, par interpolation d'une grille globale a une grille en geometrie plane. Ce changement a ete accompagne de l'utilisation, dans l'analyse d' Aladin, de donnees observees non assimilees dans Arpege : radiances du capteur Seviri installe sur Meteosat-8, temperatures a 2 m, humidites relatives a 2 m. Un impact notable de ce changement est une amelioration des previsions de precipitation a courte echeance, autant au sens statistique (scores sur environ 1,5 mois) que dans des situations convectives de debut d'ete. Les evolutions futures du systeme verront l'ajout de nouvelles observations et l'adaptation de l'analyse variationnelle a tres haute resolution pour le systeme Arome.
Environmental impact assessment for aquatic ecosystems of industrial effluents

A system of environmental impact assessment of industrial effluents is presented and discussed. Environmental assessment consists of three phases, hazard assessment, risk determination, and societary evaluation. It is regarded an integrated study of natural sciences, i.e. ecochemicology (chemical fate), ecotoxicology (toxical effects), and ecoepidemiology (biological damages); and social sciences, e.g. geography, sociology, and economy. And the outcome should be the basis of political decision making. Hazard assessment may be divided into a subphase of hazard identification from a base set of scientific information on the industrial effluent, and a second subphase of hazard analysis at a more elevated level of scientific information akin to the procedures suggested elsewhere for single chemicals. Methods of hazard assessment are laboratory experiments, e.g. chemical analysis, degradation and bioaccumulation studies, acute and chronic toxicity assessments, physical modelling, etc. Risk determination may th.
Impact of climate and anthropogenic changes on a periurban forest surface albedo derived from MODIS satellite data

Due to anthropogenic and natural factors, forest land covers changes result is the land surfaces albedo changes. The main aim of this paper is to investigate the albedo patterns dynamics due to the impact of atmospheric pollution and climate variations on a periurban forest Cernica-Branesti placed to the North-Eastern part of Bucharest city, Romania based on satellite remote sensing MODIS Terra/Aqua (Moderate Imaging Spectroradiometer) data over 2003–2012 time period. This study is based on MODIS derived biogeophysical parameters land surface BRDF/albedo products and in-situ monitoring ground data (as air temperature, aerosols distribution, relative humidity, etc.). For forest land cover changes over the same investigated period have been used also Landsat TM/ETM and IKONOS imagery. Have been analyzed also other biogeophysical effects of forest land cover change in addition to surface albedo, particularly changes in the surface moisture budget leading to shifts in the ratio of latent and sensible heat fluxes and changes in rate of land surface temperature and precipitation. Due to deforestation albedo change appears to be the most significant biogeophysical effect in temperate forests. Satellite data and climate station observations show that surface albedo changes of a forested zone placed close to a large urban area highly respond to atmospheric pollution influence and climate variations. As the physical climate system is very sensitive to surface albedo, forest ecosystems could significantly feedback to the projected climate change modeling scenarios through albedo changes.
Calcification of cyanobacterial filaments: Girvanella and the origin of lower Paleozoic lime mud

The origin of lime mud in ancient shallow-marine carbonate platforms is one of the most vexing mysteries in sedimentary geology. Possible sources previously suggested include the physical and biological disintegration of animal and algal bioclasts, mineralizing pelagic organisms, and spontaneous whitings from either abiotic precipitation or calcification of suspended picoplankton and organic matter. The styles of occurrence of micrite- walled tubes referred to Girvanella in lower Paleozoic limestones argue that occasional permineralization of mucilaginous sheaths of the benthic filamentous cyanobacteria precursor could have produced lime mud when the tubes fell apart. Estimated volumes are comparable to those calculated for the modern Bahama platform. The copious growth of cyanobacteria typical in shallow-marine settings indicates that this mechanism could account for a considerable amount of lime mud, especially in the early Paleozoic.
Concurrent altimeter and infrared observations of Rossby wave propagation near 34°N in the northeast Atlantic

We present observations of long‐wavelength baroclinic Rossby waves near 34° N in the Northeast Atlantic ocean (east of the Mid‐Atlantic Ridge) using both TOPEX/POSEIDON sea surface height (SSH) altimeter data and ERS‐1 Along‐Track Scanning Radiometer sea surface temperature (SST) measurements. Using the Fourier transforms of longitude‐time diagrams of the zonal gradients of SST and SSH we locate the spectral components corresponding to westward wave propagation and estimate wavelength, period and propagation speed. The energy associated with the propagating waves in that region is distinctly higher than in the surrounding areas. The similarities between the properties of the SST and SSH zonal gradients are remarkable with the same propagating signals clearly observed in both fields. It is believed that the interaction between the Rossby waves and the Azores current could play a major role in the amplification of the waves themselves.