Miracle-dz/UniFAR-FTUs huggingface dataset:
Statistical properties and possible supply mechanisms of tailward cold O + beams in the lobe/mantle regions

We investigate statistical properties of cold O+ beams (COBs) streaming tailward at the velocity nearly equal to the major H+ component, which were observed by Geotail/low-energy particle (LEP) instrument in the tail lobe/mantle regions at geocentric distance between 8 and 210 RE (Earth radii) during the solar-minimum period (October 1993 to March 1995). The average O+ density is ∼1.3×10−3 cm−3, which corresponds to ∼1.2 % of the proton component. Properties of the flow velocity show that it is not the weakening of the magnetospheric convection but the large parallel velocity which enables the O+ ions to remain still in the distant lobe/mantle regions. The occurrence frequency of COBs suggests that O+ ions tend to exist in the mantle-like region rather than tenuous “pure lobe” and that their existence has a clear correlation with the geomagnetic activity. On the basis of the EMF By dependence of the double-peaked COB distribution along dawn-dusk direction, it is shown that COBs exist mostly on loaded quadrants in the north–south and dawn-dusk asymmetry of sheath plasma entry caused by the IMF By effect on the dayside reconnection process. The concentration on the loaded quadrants can be seen even in geomagnetic storms. It suggests that frequent COB occurrence at active times is mainly due to the southward orientation of IMF rather than the increase of dynamic pressure itself during the geomagnetic storms. That is, the statistics show that COBs are abundant at geomagnetically active times on loaded quadrants resulting from the dayside reconnection process, where the ions of solar wind origin bear the major component, and their field-aligned velocity is larger than usual. These COBs should originate in the dayside magnetosphere and/or the polar cap regions. From the COB energy of several keV, which is rather higher than that of cusp/cleft ion outflows, the necessity of extra energization(s) to elevate parallel velocity is suggested. Clear IMF By dependence, on one hand, provides other possibilities of the COB's source such as the energetic UFI beams and the equatorially trapped ions. The requirements for each candidate so as to be a main contributor to COBs are also discussed.
A response to O. Arandjelovic's critique of "The reproducibility of research and the misinterpretation of p-values"

The main criticism of my piece in ref (2) seems to be that my calculations rely on testing a point null hypothesis, i.e. the hypothesis that the true effect size is zero. He objects to my contention that the true effect size can be zero, "just give the same pill to both groups", on the grounds that two pills can't be exactly identical. He then says "I understand that this criticism may come across as frivolous semantic pedantry of no practical consequence: of course that the author meant to say 'pills with the same contents' as everybody would have understood". Yes, that is precisely how it comes across to me. I shall try to explain in more detail why I think that this criticism has little substance.
Ideal Negative Measurements in Quantum Walks Disprove Theories Based on Classical Trajectories

We report on a stringent test of the nonclassicality of the motion of a massive quantum particle, which propagates on a discrete lattice. Measuring temporal correlations of the position of single atoms performing a quantum walk, we observe a 6σ violation of the Leggett-Garg inequality. Our results rigorously excludes (i.e., falsifies) any explanation of quantum transport based on classical, well-defined trajectories. We use so-called ideal negative measurements—an essential requisite for any genuine Leggett-Garg test—to acquire information about the atom’s position, yet avoiding any direct interaction with it. The interactionfree measurement is based on a novel atom transport system, which allows us to directly probe the absence rather than the presence of atoms at a chosen lattice site. Beyond the fundamental aspect of this test, we demonstrate the application of the Leggett-Garg correlation function as a witness of quantum superposition. Here, we employ the witness to discriminate different types of walks spanning from merely classical to wholly quantum dynamics.
Compressibility of porous rocks: Part II. New relationships

Pore volume compressibility is one of the physical properties of a reservoir that must be specified in many reservoir-engineering calculations. The main objective of this work is to provide new general formulas for pore volume compressibility versus porosity on the basis of measured compressibilities of some limestone and sandstone rocks in a wide range of porosity values and of varied type; the measurements were performed on Hungarian reservoir rock samples. The obtained laboratory results were compared with the published correlations of consolidated limestone samples as well with values for friable and strongly consolidated sandstones. The validity of using compressibility data from the literature was investigated. The measured data showed poor agreement with the published correlations.The first approach to find better and more accurate rock compressibility correlations consisted of combing all the data available from the literature, using the same formula of Horne’s type. However, this attempt did not give satisfying fitting results. In the next step, by using twelve different fitting formulas, and other comprehensive nonlinear fitting regression programs, new rock compressibility correlations for limestone and sandstone rocks, with better goodness of fit, were developed. These new correlations can be generalized and used for most of oil and gas reservoirs.
Reassessment of net surface mass balance in Antarctica

Abstract Recent in situ measurements of surface mass balance and improved calculation techniques are used to produce an updated assessment of net surface mass balance over Antarctica. A new elevation model of Antarctica derived from ERS-1 satellite altimetry supplemented with conventional data was used to delineate the ice flow drainage basins across Antarctica. The areas of these basins were calculated using the recent digital descriptions of coastlines and grounding lines. The delineation of drainage basins was achieved using an automatic procedure, which gave similar results to earlier hand-drawn catchment basins. More than 1800 published and unpublished in situ measurements of net surface mass balance from Antarctica were collated and then interpolated. A net surface mass balance map was derived from passive microwave satellite data, being employed as a forcing field to control the interpolation of the sparse in situ observations. Basinwide integrals of net surface mass balance were calculated using t.
GENESIS OF HIGH-GRADE HEMATITE OREBODIES OF THE HAMERSLEY PROVINCE, WESTERN AUSTRALIA—A DISCUSSION

Sir: Taylor et al. (2001) have presented a hypogene-supergene model for the genesis of the premium martite-microplaty hematite ores derived from banded iron formation (BIF), to replace the supergene-metamorphic model (Morris, 1980, 1985, 1998; Harmsworth et al., 1990). The new model is based on hydrothermal features in two of ten Tom Price hematite deposits, recorded previously as carbonate metasomatism of BIF (Ewers and Morris, 1981), and as localized postore metasomatism (Harmsworth et al., 1990; Morris, 1998). From new data, Taylor et al. (2001) proposed that hypogene leaching of free silica with addition of further siderite in BIF, followed by compaction, produced a general hematite ore precursor. During deep weathering episodes, or even within Tertiary weathering profiles, oxidation of magnetite to martite, and siderite to microplaty hematite and ankerite, followed by leaching of residual gangue, enriched this modified BIF to martite-microplaty hematite ore. In contrast, in the supergene-metamorphic model, martite-microplaty hematite ore genesis is linked to metamorphism of precursor ores of the Phanerozoic supergene martite-goethite type. These comprise about 90 percent of the Hamersley BIF-hosted resource, and deposits range to over a billion tonnes (Harmsworth et al., 1990) and >250 m deep, with high phosphorus levels (0.07–0.17% P). Although stratigraphically thinned by leaching (~35%) they maintain primary BIF banding and texture, with gangue minerals altered to phosphorus-bearing goethite pseudomorphs. Their martite-microplaty hematite analogues (< 0.06 % P) are attributed to Proterozoic supergene enrichment of BIF, with burial metamorphism partly converting the goethite pseudomorphs to secondary, largely microplaty, hematite, yet preserving the primary banding. Some 20 known deposits of this type range from small pockets of enrichment to the massive Mount Whaleback (1700 Mt). Later re-exposures of the microplaty hematite deposits produced further stratigraphic thinning (total ~45–50 %), with loss of phosphorus by leaching of remnant goethite. However, significant …
Application of Meteorological Satellite Data in Analysis and Forecasting

Abstract : The report represents the combined efforts of personnel of the Applications Group, National Environmental Satellite Center (NESC), now the National Environmental Satellite Service (NESS); the NAVAL AIR SYSTEMS COMMAND Project FAMOS; and the Satellite Section, USAF ENVIRONMENTAL TECHNICAL APPLICATIONS CENTER (ETAC). Topics discussed include the following: Satellite cloud atlas and glossary; Synoptic cloud patterns; Application of satellite data to synoptic analysis in the tropics; Local phenomena; Infrared.
Large-N expansion of the 2-matrix model

We present a method, based on loop equations, to compute recursively, all the terms in the large N topological expansion of the free energy for the 2-hermitean matrix model. We illustrate the method by computing the first subleading term, i.e. the free energy of a statistical physics model on a discretized torus.
Linear series and existence of branched covers

In this paper, we use the perspective of linear series, and in particular results following from the degeneration tools of limit linear series, to give a number of new results on existence and non-existence of branched covers of the projective line in positive characteristic. Our results are both in terms of ramification indices and the sharper invariant of monodromy groups, and the first class of results are obtained by intrinsically algebraic and positive-characteristic arguments.
Compositional variations of olivines and pyroxenes in chondritic interplanetary dust particles

We report here analyses of olivines and pyroxenes, and petrofabrics of 27 chondritic interplanetary dust particles (IDPs), comparing those from anhydrous and hydrous types. Approximately 40% of the hydrous particles contain diopside, a probable indicator of parent body thermal metamorphism, while this mineral is rarely present in the anhydrous particles. Based on this evidence, we find that hydrous and anhydrous IDPs are, in general, not directly related, and we conclude that olivine and pyroxene major-element compositions can be used to help discriminate between IDPs that are (1) predominantly nebular condensates, and lately resided in anhydrous or icy (no liquids) primitive parent bodies, and (2) those originating from more geochemically active parent bodies (probably hydrous and anhydrous asteroids).
A global monthly sea surface temperature climatology

Abstract A new global 2°×2° monthly sea surface temperature (SST) climatology, primarily derived from a 1950–1979-based SST climatology from the Climate Analysis Center (CAC), is presented and described. The CAC climatology has been modified by using data from the Comprehensive Ocean-Atmosphere Data Set to improve the SST estimates in the regions of the Kuroshio and the Gulf Stream. This results in considerably larger and more realistic SST gradients in these regions. This modified climatology is smoothed in time using a truncated Fourier series to eliminate mean annual cycle fluctuations of three months or less, and finally, some spatial smoothing is applied over the high-latitude southern oceans. This new SST climatology, which we call the Shea-Trenberth-Reynolds (STR) climatology, is compared with the Alexander and Mobley (AM) SST climatology often used as a lower boundary condition by general circulation models. Significant differences are noted. Generally, the STR climatology is warmer in the Norther.
Subsurface Quasi-Decadal Fluctuations in the North Atlantic

Abstract Analysis of hydrographic time series data at ocean station 5 (Panulirus) and along the Labrador continental margin is used to investigate the subsurface structure associated with the North Atlantic quasi-decadal SST fluctuation. Quasi-decadal fluctuations of both temperature and salinity are confined to the upper water column that is ventilated by the seasonal cycle. In the subtropical gyre, they are independent of the variations of the gyre baroclinic transport. On the Labrador continental margin, the quasi-decadal fluctuations are confined to the upper portion of the Labrador Current. The quasi-decadal fluctuation appears to be surface forced; in the subtropical gyre, this is predominantly by latent heat flux. In the subpolar gyre, latent and sensible heat flux alone cannot account for the in-phase variation of temperature and salinity. Instead, the variation involves upper-ocean convective mixing whose strength is modulated by the density of the winter-cooled surface water. It has been noted t.
Universal Randomized Guessing Subjected to Distortion

In this paper, we consider the problem of guessing a sequence subject to a distortion constraint. Specifically, we assume the following game between Alice and Bob: Alice has a sequence $\bx$ of length $n$. Bob wishes to guess $\bx$, yet he is satisfied with finding any sequence $\hat{\bx}$ which is within a given distortion $D$ from $\bx$. Thus, he successively submits queries to Alice, until receiving an affirmative answer, stating that his guess was within the required distortion. Finding guessing strategies which minimize the number of guesses (the \emph{guesswork}), and analyzing its properties (e.g., its $\rho$--th moment) has several applications in information security, source and channel coding. Guessing subject to a distortion constraint is especially useful when considering contemporary biometrically--secured systems, where the"password"which protects the data is not a single, fixed vector but rather a \emph{ball of feature vectors} centered at some $\bx$, and any feature vector within the ball results in acceptance. We formally define the guessing problem under distortion in \emph{four different setups}: memoryless sources, guessing through a noisy channel, sources with memory and individual sequences. We suggest a randomized guessing strategy which is asymptotically optimal for all setups and is \emph{five--fold universal}, as it is independent of the source statistics, the channel, the moment to be optimized, the distortion measure and the distortion level.
New seismic evidence for a major geological boundary at shallow depth, N Devon

Recently acquired marine reflection data provide evidence for a major geological boundary at shallow depth under the southern Bristol Channel, in the hangingwall block of the Bristol Channel thrust. The boundary is recognized to equate with the top surface of a high velocity layer previously identified along refraction/wide-angle reflection seismic lines in the north Devon area. Depth estimates from the reflection data and from a new interpretation of the earlier refraction data are combined to produce a contour map of the shallow boundary in the south-central Bristol Channel and north Devon areas. The boundary has a WSW-ENE regional trend and lies at a depth of less than 2 km immediately north of the Devon coast. It is truncated to the north by the Bristol Channel thrust and deepens southwards across north Devon and west Somerset. The boundary is interpreted as the top surface of a major litho-stratigraphic unit older than the outcropping Devonian sequence and in normal stratigraphic contact with it. However, in the absence of regional geological control the nature and age of the underlying high-velocity layer remain uncertain.
Cenozoic Environmental Changes in the Northern Qaidam Basin Inferred from n‐alkane Records

Cenozoic climatic and environmental changes in the arid Asian interior, and their possible relations with global climatic changes and the Tibetan Plateau uplift, have been intensively investigated and debated over past decades. Here we present 40‐Myr (million years)‐long n‐alkane records from a continuous Cenozoic sediment sequence in the Dahonggou Section, Qaidam Basin, northern Tibetan Plateau, to infer environmental changes in the northern basin. A set of n‐alkane indexes, including ACL, CPI and Paq, vary substantially and consistently throughout the records, which are interpreted to reflect relative contributions from terrestrial vascular plants vs. aquatic macrophytes, and thus indicate depositional environments. ACL values vary between 21 and 30; CPI values range from 1.0 to 8.0; and Paq values change from <0.1 to 0.8 over the past 40‐Myr. We have roughly identified two periods, at 25.8–21.0 Ma (million years ago) and 13.0–17.5 Ma, with higher ACL and CPI and lower Paq values indicating predominant lacustrine environments. Lower ACL and CPI values, together with higher Paq values, occurred at >25.8 Ma, 17.5–21.0 Ma, and <13.0 Ma, corresponding to alluvial fan/river deltaic deposits and shallow lacustrine settings, consistent with the observed features in sedimentological facies. The inferred Cenozoic environmental changes in the northern Qaidam Basin appear to correspond to global climatic changes.
Time-varying Coefficients Estimation in Differential Equation Models with Noisy Time-varying Covariates

We study the problem of estimating time-varying coefficients in ordinary differential equations. Current theory only applies to the case when the associated state variables are observed without measurement errors as presented in \cite{chenwu08b,chenwu08}. The difficulty arises from the quadratic functional of observations that one needs to deal with instead of the linear functional that appears when state variables contain no measurement errors. We derive the asymptotic bias and variance for the previously proposed two-step estimators using quadratic regression functional theory.
REEL-BF Design: Achieving the SDP Bound for Downlink Beamforming With Arbitrary Shaping Constraints

This paper considers the beamforming design for a multiuser multiple-input single-output downlink with an arbitrary number of (context specific) shaping constraints. In this setup, the state-of-the-art beamforming schemes cannot attain the well known performance bound promised by the semidefinite program (SDP) relaxation technique. To close the gap, we propose a redundant-signal embedded linear beamforming (REEL-BF) scheme, where each user is assigned with one information beamformer and several shaping beamformers. It is shown that the proposed REEL-BF scheme can perform general rank-$K$ beamforming for user symbols in a low-complexity and structured manner. In addition, sufficient conditions are derived to guarantee that the REEL-BF scheme always achieves the SDP bound for linear beamforming schemes. Based on such conditions, an efficient algorithm is then developed to obtain the optimal REEL-BF solution in polynomial time. Numerical results demonstrate that the proposed scheme enjoys substantial performance gains over the existing alternatives.
The First Stars

▪ Abstract We review recent theoretical results on the formation of the first stars in the universe, and emphasize related open questions. In particular, we discuss the initial conditions for Population III star formation, as given by variants of the cold dark matter cosmology. Numerical simulations have investigated the collapse and the fragmentation of metal-free gas, showing that the first stars were predominantly very massive. The exact determination of the stellar masses, and the precise form of the primordial initial mass function, is still hampered by our limited understanding of the accretion physics and the protostellar feedback effects. We address the importance of heavy elements in bringing about the transition from an early star formation mode dominated by massive stars to the familiar mode dominated by low-mass stars at later times. We show how complementary observations, both at high redshifts and in our local cosmic neighborhood, can be utilized to probe the first epoch of star formation.
Galapagos Hot Spot-Spreading Center System: 1. Spatial petrological and geochemical variations (83°W-101°W)

We report on the petrology and geochemistry of basalts dredged at 40--50 km intervals along the Galapagos Spreading Center, between 83/sup 0/W and 101/sup 0/W (40 stations). Emphasis is on spatial variations of 'whole rock' major elements, rare earths, trace metals of the first transition series, and the nature of phenocryst assemblages and their abundances. These results provide new constraints on the nature and scale of mantle source heterogeneities, melting conditions, thermal field, and dynamics of crustal formation of the region. We suggest that ridge segments outside the high magnetic amplitude zone are at a steady state as a result of passive seafloor spreading. Basalts from these segments are apparently derived from an asthenosphere relatively uniformally depleted in incompatible elements, which appears of worldwide extent. We reject Vogt and DeBoer's (1976) model invoking damming at fracture zones of subaxial asthenosphere flow of crystal slushes and increasing fractional crystallization down the flow line, because this model would not explain the gradients in REE observed about the Galapagos Platform. Our preferred model combines the mantle-plume binary mixing model of Schilling (1973) with the concept of recurring rift propagation proposed by Hey (1977a). We further propose that pulsating mantle plume flux, perhaps inmore » the form of a chain of blobs, may initiate the development of new rifts and their propagation. The present position of the tips of such new propagating rifts locate the wave fronts of such pulsating mantle plume flow. A two million year period is suggested for the last 4 m.y. from Wilson and Hey's (1979) information Rigorous testing of our preferred model is possible. « less
Initiation of shear instability in three-dimensional elastodynamics

[1] Earthquake nucleation may begin with a stable quasi-static localization of fault slip. This long-term process, which conditions the fault for the rupture, is followed by a dynamic and unstable phase that we call initiation and ends with the onset of rupture propagation. In this paper, we investigate the three-dimensional elastodynamics of this unstable initiation phase both analytically and numerically. The fault model consists of two symmetric semi-infinite elastic bodies in frictional contact across a flat interface with a slip-weakening law and loaded until its sliding threshold is reached. On the basis of our previous studies in two dimensions, we generalize the linear stability and the spectral analysis and then solve analytically the "dominant part" approximation for the homogeneous infinite fault. We then derive the slip pattern on the fault, the decay of the displacement amplitude in the media, and its growth in time. The model also gives a theoretical approximation for the time of initiation. To test the dominant part approximation, we compare it with the numerical solution in the case of a concentrated perturbation. Finally, we find that unlike the infinite fault, finite faults of a given geometry allow a domain of stability that depends on the fault size. When a finite fault becomes unstable and rupture initiates, the slip growth is determined by a single dominant eigenmode. The duration of the initiation phase varies strongly with the size and geometry of the fault, especially when it is close to the stability limit.