Miracle-dz/UniFAR-FTUs huggingface dataset:
Forest Aboveground Biomass Estimation and Response to Climate Change Based on Remote Sensing Data

As the largest and most important natural terrestrial ecosystem, forest plays a crucial role in reducing the concentrations of greenhouse gases in the atmosphere, mitigating global warming, maintaining the global ecological balance, and promoting global biological evolution and community succession. The accurate and rapid assessment of forest biomass is highly significant for estimating the regional carbon budget and monitoring forest change. In this study, Landsat images and China’s National Forest Continuous Inventory data of 1999, 2004, 2009, and 2014 were used to establish extreme gradient boosting (XGBoost) models for forest aboveground biomass (AGB) estimation based on forest type in the Xiangjiang River Basin, Hunan Province, China. Kriging interpolation of the AGB residuals was used to correct the error of AGB estimation. Then, a new XGBoost model was established using the final corrected AGB maps and climate data to estimate the AGB under different climate scenarios during the 2050s and 2070s. The results indicated that AGB estimation using the XGBoost model with correction via Kriging interpolation of the AGB residuals can significantly improve the accuracy of AGB estimation. The total AGB of the study area increased over time from 1999 to 2014, indicating that the forest quality improved in the study area. Under the different climate scenarios, the total AGB during the 2050s and 2070s was predicted to decline continuously with increasing of greenhouse gas emissions, indicating that greenhouse gas emissions have a negative impact on forest growth. The results of this study can provide data support for evaluating the ecological function and value of forest ecosystems, and for formulating reasonable forest management measures to mitigate the effects of climate change.
Master equation for She–Leveque scaling and its classification in terms of other Markov models of developed turbulence

The statistics of velocity increments in homogeneous and isotropic turbulence exhibit universal features in the limit of infinite Reynolds numbers. After Kolmogorov’s scaling law from 1941, many turbulence models aim for capturing these universal features, some are known to have an equivalent formulation in terms of Markov processes. We derive the Markov process equivalent to the particularly successful scaling law postulated by She and Leveque. The Markov process is a jump process for velocity increments u(r) in scale r in which the jumps occur randomly but with deterministic width in u. From its master equation we establish a prescription to simulate the She–Leveque process and compare it with Kolmogorov scaling. To put the She–Leveque process into the context of other established turbulence models on the Markov level, we derive a diffusion process for u(r) using two properties of the Navier–Stokes equation. This diffusion process already includes Kolmogorov scaling, extended self-similarity and a class of random cascade models. The fluctuation theorem of this Markov process implies a ‘second law’ that puts a loose bound on the multipliers of the random cascade models. This bound explicitly allows for instances of inverse cascades, which are necessary to satisfy the fluctuation theorem. By adding a jump process to the diffusion process, we go beyond Kolmogorov scaling and formulate the most general scaling law for the class of Markov processes having both diffusion and jump parts. This Markov scaling law includes She–Leveque scaling and a scaling law derived by Yakhot.
THE METALLICITY EVOLUTION OF INTERACTING GALAXIES

Nuclear inflows of metal-poor interstellar gas triggered by galaxy interactions can account for the systematically lower central oxygen abundances observed in local interacting galaxies. Here, we investigate the metallicity evolution of a large set of simulations of colliding galaxies. Our models include cooling, star formation, feedback, and a new stochastic method for tracking the mass recycled back to the interstellar medium from stellar winds and supernovae. We study the influence of merger-induced inflows, enrichment, gas consumption, and galactic winds in determining the nuclear metallicity. The central metallicity is primarily a competition between the inflow of low-metallicity gas and enrichment from star formation. An average depression in the nuclear metallicity of ∼0.07 is found for gas-poor disk–disk interactions. Gas-rich disk–disk interactions, on the other hand, typically have an enhancement in the central metallicity that is positively correlated with the gas content. The simulations fare reasonably well when compared to the observed mass–metallicity and separation–metallicity relationships, but further study is warranted.
ac susceptibility and static magnetization measurements of CeRu2Si2 at small magnetic fields and ultralow temperatures

The magnetic properties of CeRu 2 Si 2 at microkelvin temperatures (down to 170 μK) and ultrasmall magnetic fields (0.02∼6.21 mT) are investigated experimentally. The simultaneously measured ac susceptibility and static magnetization show neither evidence of the magnetic ordering, superconductivity down to the lowest temperatures nor conventional Landau Fermi-Liquid behavior. The results imply the magnetic transition temperature in undoped CeRu 2 Si 2 is very close to absolute 0 K. The possibility for proximity of CeRu 2 Si 2 to the quantum critical point without any doping is discussed.
Global analysis of neutrino masses, mixings and phases: entering the era of leptonic CP violation searches

We perform a global analysis of neutrino oscillation data, including high-precision measurements of the neutrino mixing angle ${\ensuremath{\theta}}_{13}$ at reactor experiments, which have confirmed previous indications in favor of ${\ensuremath{\theta}}_{13}g0$. Recent data presented at the Neutrino 2012 conference are also included. We focus on the correlations between ${\ensuremath{\theta}}_{13}$ and the mixing angle ${\ensuremath{\theta}}_{23}$, as well as between ${\ensuremath{\theta}}_{13}$ and the neutrino $CP$-violation phase $\ensuremath{\delta}$. We find interesting indications for ${\ensuremath{\theta}}_{23}l\ensuremath{\pi}/4$ and possible hints for $\ensuremath{\delta}\ensuremath{\sim}\ensuremath{\pi}$, with no significant difference between normal and inverted mass hierarchy.
Robust Distributed Hybrid Beamforming in Coordinated Multi-User Multi-Cell mmWave MIMO Systems Relying on Imperfect CSI

Novel hybrid beamformer designs are conceived for a multi-user multi-cell (MUMC) mmWave system relying on base station (BS) coordination and total transmit power minimization subject to realistic signal-to-interference-plus-noise ratio (SINR) constraints at each mobile station (MS). Initially, a semidefinite relaxation (SDR)-based approach is developed for a centralized MUMC system to determine the fully digital beamformer having perfect CSI. Subsequently, a Bayesian learning (BL) technique is harnessed for decomposing the fully-digital (FD) solution into its analog and digital components for constructing a hybrid transceiver. Next, an alternating direction method of multipliers (ADMM) based distributed hybrid beamformer is designed for the same system, which requires only local CSI and limited information exchange among the BSs, thus avoiding the excessive signalling overheads required by the centralized approach. Then we further extend both the centralized and the above distributed hybrid designs to construct robust beamformers that minimize the worst-case transmit power with imperfect CSI. Our robust beamforming techniques leverage the S-lemma, which is eminently suitable for the infinitely many constraints arising from the associated CSI uncertainty. Finally, our simulation results demonstrate the improved performance of the proposed centralized and distributed methods over the system having no coordination.
COSMOLOGICAL SIMULATIONS OF MILKY WAY-SIZED GALAXIES

We introduce a new set of eight Milky Way-sized cosmological simulations performed using the AMR code Adaptive Refinement Tree + Hydrodynamics in a ΛCDM cosmology. The set of zoom-in simulations covers present-day virial masses that range from to and is carried out with our simple but effective prescriptions for deterministic star formation (SF) and “explosive” stellar feedback. The work focuses on showing the goodness of the simulated set of “field” Milky Way-sized galaxies. To this end, we compare some of the predicted physical quantities with the corresponding observed ones. Our results are as follows. (a) In agreement with some previous works, we found curves of circular velocity that are flat or slightly peaked. (b) All simulated galaxies with a significant disk component are consistent with the observed Tully–Fisher, radius–mass, and cold gas–stellar mass correlations of late-type galaxies. (c) The disk-dominated galaxies have stellar specific angular momenta in agreement with those of late-type galaxies, with values around 103 km s−1 kpc−1. (d) The SF rates at z = 0 of all runs but one are comparable to those estimated for the star-forming galaxies. (e) The two most spheroid-dominated galaxies formed in halos with late active merger histories and late bursts of SF, but the other run that ends also dominated by a spheroid never had major mergers. (f) The simulated galaxies lie in the semi-empirical correlation of stellar to halo mass of local central galaxies, and those that end up as disk-dominated evolve mostly along the low-mass branch of this correlation. Moreover, the growth histories of baryonic and stellar mass of these galaxies are proportional to their growth histories of halo mass over the last 6.5–10 Gyr. (g) Within the virial radii of the simulations, –50% of the baryons are missed; the amount of gas in the halo is similar to the amount in stars in the galaxy, and most of this gas is in the warm–hot phase. (h) The profiles of vertical gas velocity dispersion, (r), are nearly flat and can be mostly explained by the kinetic energy injected by stars. The average values of increase at higher redshifts, following roughly the shape of the SF history.
Finite Temperature Excitations of a Trapped Bose Gas

We present a detailed study of the temperature dependence of the condensate and noncondensate density profiles of a Bose-condensed gas in a parabolic trap. These quantities are calculated self-consistently using the Hartree-Fock-Bogoliubov equations within the Popov approximation. Below the Bose-Einstein transition the excitation frequencies have a relatively weak temperature dependence even though the condensate is strongly depleted. As the condensate density goes to zero through the transition, the excitation frequencies are strongly affected and approach the frequencies of a noninteracting trapped gas in the high temperature limit. {copyright} {ital 1997} {ital The American Physical Society}
Noether derivation of exact conservation laws for dissipationless reduced-fluid models

The energy-momentum conservation laws for general reduced-fluid (e.g., gyrofluid) models are derived by Noether method from a general reduced variational principle. The reduced canonical energy-momentum tensor (which is explicitly asymmetric and has the Minkowski form) exhibits polarization and magnetization effects associated with dynamical reduction. In particular, the asymmetry in the reduced canonical momentum-stress tensor produces a nonvanishing reduced intrinsic torque that can drive spontaneous toroidal rotation in axisymmetric tokamak plasmas.
Fault-tolerant quantum computation for singlet-triplet qubits with leakage errors

We describe and analyze leakage errors of singlet-triplet qubits. Even though leakage errors are a natural problem for spin qubits encoded using quantum dot arrays, they have obtained little attention in previous studies. We describe the realization of leakage correction protocols that can be implemented together with the quantum error correction protocol of the surface code. Furthermore we construct explicit leakage reduction units that need, in the ideal setup, as few as three manipulation steps. Our study shows that leakage errors can be corrected without the need of measurements and at the cost of only a few additional ancilla qubits and gate operations compared to standard quantum error correction codes.
Galaxy alignment on large and small scales

Abstract Galaxies are not randomly distributed across the universe but showing different kinds of alignment on different scales. On small scales satellite galaxies have a tendency to distribute along the major axis of the central galaxy, with dependence on galaxy properties that both red satellites and centrals have stronger alignment than their blue counterparts. On large scales, it is found that the major axes of Luminous Red Galaxies (LRGs) have correlation up to 30Mpc/h. Using hydro-dynamical simulation with star formation, we investigate the origin of galaxy alignment on different scales. It is found that most red satellite galaxies stay in the inner region of dark matter halo inside which the shape of central galaxy is well aligned with the dark matter distribution. Red centrals have stronger alignment than blue ones as they live in massive haloes and the central galaxy-halo alignment increases with halo mass. On large scales, the alignment of LRGs is also from the galaxy-halo shape correlation, but with some extent of mis-alignment. The massive haloes have stronger alignment than haloes in filament which connect massive haloes. This is contrary to the naive expectation that cosmic filament is the cause of halo alignment.
Critical points of the cosmic velocity field and the uncertainties in the value of the Hubble constant

The existence of critical points for the peculiar velocity field is a natural feature of the correlated vector field. These points appear at the junctions of velocity domains with different orientations of their averaged velocity vectors. Since peculiar velocities are the important cause of the scatter in the Hubble expansion rate, we propose that a more precise determination of the Hubble constant can be made by restricting analysis to a subsample of observational data containing only the zones around the critical points of the peculiar velocity field, associated with voids and saddle points. On large-scales the critical points, where the first derivative of the gravitational potential vanishes, can easily be identified using the density field and classified by the behavior of the Hessian of the gravitational potential. We use high-resolution N-body simulations to show that these regions are stable in time and hence are excellent tracers of the initial conditions. Furthermore, we show that the variance of the Hubble flow can be substantially minimized by restricting observations to the subsample of such regions of vanishing velocity instead of aiming at increasing the statistics by averaging indiscriminately using the full data sets, as is the common approach.
Student emotional response to the lesser kestrel environmental and sustainability education program

Abstract Emotion is a central aspect for protecting the environment in environmental and sustainability education (ESE). As such, positive emotions toward nature can increase motivation to learn and take environmental action. This qualitative case study explored the complex interrelationship among place-based education, emotions and values related to ESE, academic social and emotional learning, and explored the situated notion of emotions in the context of environmental citizenship. The emotions of 59 fifth-grade students, who were engaged in a program to protect the Lesser Kestrel, were explored. The findings suggest that the outcomes of the Lesser Kestrel program were complex and mostly positive in activating students’ emotions. The results indicate that ESE programs should focus on situated emotions, due to their important role in promoting powerful learning experiences and environmental citizenship, which may mitigate the environmental crisis, along with moral issues that affect the well-being of the individual, and social and natural environments.
Water-Worked Gravel Bed: State-of-the-Art Review

In a natural gravel-bed stream, the bed that has an organized roughness structure created by the streamflow is called the water-worked gravel bed (WGB). Such a bed is entirely different from that created in a laboratory by depositing and spreading gravels in the experimental flume, called the screeded gravel bed (SGB). In this paper, a review on the state-of-the-art research on WGBs is presented, highlighting the role of water-work in determining the bed topographical structures and the turbulence characteristics in the flow. In doing so, various methods used to analyze the bed topographical structures are described. Besides, the effects of the water-work on the turbulent flow characteristics, such as streamwise velocity, Reynolds and form-induced stresses, conditional turbulent events and secondary currents in WGBs are discussed. Further, the results form WGBs and SGBs are compared critically. The comparative study infers that a WGB exhibits a higher roughness than an SGB. Consequently, the former has a higher magnitude of turbulence parameters than the latter. Finally, as a future scope of research, laboratory experiments should be conducted in WGBs rather than in SGBs to have an appropriate representation of the flow field close to a natural stream.
JET PROPAGATIONS, BREAKOUTS, AND PHOTOSPHERIC EMISSIONS IN COLLAPSING MASSIVE PROGENITORS OF LONG-DURATION GAMMA-RAY BURSTS

We investigate the following by two-dimensional axisymmetric relativistic hydrodynamical simulations: (1) jet propagations through an envelope of a rapidly rotating and collapsing massive star, which is supposed to be a progenitor of long-duration gamma-ray bursts (GRBs); (2) breakouts and subsequent expansions into stellar winds; and (3) the accompanying photospheric emissions. We find that if the envelope rotates uniformly almost at the mass shedding limit, its outer part eventually stops contracting when the centrifugal force becomes large enough. Then another shock wave is formed, propagates outward, and breaks out of the envelope into the stellar wind. Whether the jet or the centrifugal bounce-induced shock breaks out earlier depends on the timing of jet injection. If the shock breakout occurs earlier, owing to a later injection, the jet propagation and subsequent photospheric emissions are affected substantially. We pay particular attention to observational consequences of the difference in the timing of jet injection. We calculate optical depths to find the location of photospheres, extracting densities, and temperatures at appropriate retarded times from the hydrodynamical data. We show that the luminosity and observed temperature of the photospheric emissions are both much lower than those reported in previous studies. Although luminosities are still high enough for GRBs, the observed temperatures are lower than the energy at the spectral peak expected by the Yonetoku relation. This may imply that energy exchanges between photons and matter are terminated deeper inside or that some non-thermal processes are operating to boost photon energies.
Can standard cosmological models explain the observed Abell cluster bulk flow

Lauer \& Postman (LP) observe that all Abell clusters with redshifts less than 15,000\kms\ appear to be participating in a bulk flow of 689 km s$^{-1}$ with respect to the Cosmic Microwave Background. We find this result difficult to reconcile with all popular models for large-scale structure formation that assume Gaussian initial conditions. This conclusion is based on Monte-Carlo realizations of the LP data, drawn from large Particle-Mesh $N$-body simulations. We have taken special care to treat properly the longest-wavelength components of the power spectra. Bulk flows with amplitude as large as that reported by LP are not uncommon in the Monte-Carlo datasets. However, the $\chi^2$ of the observed bulk flow, taking into account the anisotropy of the error ellipsoid, is much more difficult to match in the simulations. The models examined are ruled out at confidence levels between 94\% and 98\%. Any model that has {\it intrinsic} flows of less than 480\kms\ on the scales probed by LP scales can be ruled out at a similar level.
Lightening-like interactions in nuclear collisions at CERN large hadron collider

Umm Al-Qura University, Faculty of Applied Science, Physics Department, P.O. Box (715),Makkah 21955, Saudi ArabiaE-mail: nafelemban@uqu.edu. saA simple basic model for describing proton-nucleus (p+A) and nucleus-nucleus (A+A) colli-sions has been the intra-nuclear cascade model, where the interactions are simulated by a sequenceof binary nucleon-nucleon (NN) collisions. This model helped to establish many scientiﬁc con-cepts and also creates the foundation for more modern simulation codes, especially at low andintermediate energies. In this paper, we present a new Monte Carlo model for p+A and A+Acollisions at high CERN Large Hadron collider energies. The model implements HIJING codewith a collective cascade recipe, that induces lightening-like effect in a large nucleus. A singlecollision (lightening) event is shown to be a complex process: A primary interacting nucleonpasses its energy to the surrounding nucleons in a large nucleus. This new simulation code isshown to be good to reproduce the Large Hadron collider (LHC) data, especially the chargedparticle pseudorapidity density in p+Pb and Pb+Pb collisions at LHC energies.The European Physical Society Conference on High Energy Physics22–29 July 2015Vienna, Austria
The Sun and stars as the primary energy input in planetary atmospheres

Abstract Proper characterization of the host star to a planet is a key element to the understanding of its overall properties. The star has a direct impact through the modification of the structure and evolution of the planet atmosphere by being the overwhelmingly larger source of energy. The star plays a central role in shaping the structure, evolution, and even determining the mere existence of planetary atmospheres. The vast majority of the stellar flux is well understood thanks to the impressive progress made in the modeling of stellar atmospheres. At short wavelengths (X-rays to UV), however, the information is scarcer since the stellar emission does not originate in the photosphere but in the chromospheric and coronal regions, which are much less understood. The same can be said about particle emissions, with a strong impact on planetary atmospheres, because a detailed description of the time-evolution of stellar wind is still lacking. Here we review our current understanding of the flux and particle emissions of the Sun and low-mass stars and briefly address their impact in the context of planetary atmospheres.