Miracle-dz/UniFAR-FTUs huggingface dataset:
Topography of the 400 km discontinuity from observations of long-period P400P phases

SUMMARY New evidence is presented for lateral variation of the depth of upper mantle discontinuities. This evidence is derived from an analysis of amplitude of P400P phases (underside reflections from the 400 km discontinuity) for great circle paths with bounce points in the upper mantle near the Hawaii-Emperor hotspot chain. The data are long-period, from WWSSN, SRO and RSTN stations. The epicentral distance ranges from 95° to 115°, which ensures that no other major phases arrive in the time window of interest. Observed P400P amplitudes are compared with synthetic amplitudes for both a laterally homogeneous model and models including 3-D topography on the discontinuities. The observations permit models of topography that can be characterized by undulations of the 400 km discontinuity with wavelengths in the range 600–2000 km, and peak-to-peak amplitude of the order of 30–40 km. Such long-wavelength structure causes quite strong (de)focusing of PdP phases; synthetic PdP waveforms reveal that topography not only affects its amplitude, but also smears out the PdP wave, causing overlap between different PdP phases. This mechanism is proposed as the reason for the lack of well-developed PdP phases reported in the literature. The fact that the waveforms can be seriously distorted prohibits the use of PdP phases in a waveform inversion. The curvature of the discontinuity can be explained as the signature of convection currents crossing the discontinuity. Although the data cover the Hawaii hotspot, no signature of a plume structure can be detected in the data, probably because the resolving power of the data is too low.
Asymptotic behaviour of the fifth Painlevé transcendents in the space of initial values

We study the asymptotic behaviour of the solutions of the fifth Painlevé equation as the independent variable approaches zero and infinity in the space of initial values. We show that the limit set of each solution is compact and connected and, moreover, that any solution with an essential singularity at zero has an infinite number of poles and zeroes, and any solution with an essential singularity at infinity has infinite number of poles and, moreover, takes the value unity infinitely many times.
The χ Factor: Determining the Strength of Activity in Low‐Mass Dwarfs

We describe a new, distance‐independent method for calculating the magnetic activity strength in low‐mass dwarfs, LHα/Lbol. Using a well‐observed sample of nearby stars and cool standards spanning spectral type M0.5 to L0, we compute χ, the ratio between the continuum flux near Hα and the bolometric flux, fλ6560/fbol. This ratio can be multiplied by the measured equivalent width of the Hα emission line to yield LHα/Lbol. We provide χ values for all objects in our sample, and also fits to χ as a function of color and average values by spectral type. This method was used by West et al. to examine trends in magnetic activity strength in low‐mass stars.
Online Sampling from Log-Concave Distributions

Given a sequence of convex functions $f_0, f_1, \ldots, f_T$, we study the problem of sampling from the Gibbs distribution $\pi_t \propto e^{-\sum_{k=0}^tf_k}$ for each epoch $t$ in an online manner. Interest in this problem derives from applications in machine learning, Bayesian statistics, and optimization where, rather than obtaining all the observations at once, one constantly acquires new data, and must continuously update the distribution. Our main result is an algorithm that generates roughly independent samples from $\pi_t$ for every epoch $t$ and, under mild assumptions, makes $\mathrm{polylog}(T)$ gradient evaluations per epoch. All previous results imply a bound on the number of gradient or function evaluations which is at least linear in $T$. Motivated by real-world applications, we assume that functions are smooth, their associated distributions have a bounded second moment, and their minimizer drifts in a bounded manner, but do not assume they are strongly convex. In particular, our assumptions hold for online Bayesian logistic regression, when the data satisfy natural regularity properties, giving a sampling algorithm with updates that are poly-logarithmic in $T$. In simulations, our algorithm achieves accuracy comparable to an algorithm specialized to logistic regression. Key to our algorithm is a novel stochastic gradient Langevin dynamics Markov chain with a carefully designed variance reduction step and constant batch size. Technically, lack of strong convexity is a significant barrier to analysis and, here, our main contribution is a martingale exit time argument that shows our Markov chain remains in a ball of radius roughly poly-logarithmic in $T$ for enough time to reach within $\varepsilon$ of $\pi_t$.
DNN-Based Semantic Model for Rescoring N-best Speech Recognition List

The word error rate (WER) of an automatic speech recognition (ASR) system increases when a mismatch occurs between the training and the testing conditions due to the noise, etc. In this case, the acoustic information can be less reliable. This work aims to improve ASR by modeling long-term semantic relations to compensate for distorted acoustic features. We propose to perform this through rescoring of the ASR N-best hypotheses list. To achieve this, we train a deep neural network (DNN). Our DNN rescoring model is aimed at selecting hypotheses that have better semantic consistency and therefore lower WER. We investigate two types of representations as part of input features to our DNN model: static word embeddings (from word2vec) and dynamic contextual embeddings (from BERT). Acoustic and linguistic features are also included. We perform experiments on the publicly available dataset TED-LIUM mixed with real noise. The proposed rescoring approaches give significant improvement of the WER over the ASR system without rescoring models in two noisy conditions and with n-gram and RNNLM.
Case studies of aerosol remote sensing in the vicinity of clouds

[1] Studying the spatial variability of aerosol properties in the vicinity of clouds is essential to our ability to determine aerosol direct and indirect effects on climate. In this paper, we describe aerosol observations collected near cloud edges by an airborne Sun photometer over dark ocean waters. Focusing on case studies of aerosol measurements near eight cloud edges within a dissipating stratiform cloud deck, we compare the airborne Sun photometer observations to retrievals of aerosol properties using the standard Moderate Resolution Imaging Spectroradiometer (MODIS) aerosol algorithm applied to 500-m-resolution MODIS spectral reflectances. We find a persistent, spectrally neutral increase in the Sun photometer–derived aerosol optical depth (AOD) of up to 10% (0.015) in the 2-km distances closest to the edges of several distinct clouds. At midvisible wavelengths, the MODIS AOD retrievals show similar increases toward cloud edges, although a larger increase in AOD is found in the MODIS along-scan direction. At short-wave infrared (SWIR) wavelengths (1240–2130 nm), the MODIS-derived AOD increases near cloud edges are of the order of 0.03 and as such three times as large as the Sun photometer–derived values. Hence, in contrast to recently discussed “bluing” of aerosols near cloud edges, i.e., a preferential apparent increase in the visible reflectances of clear-sky pixels due to 3-D radiative transfer effects in the vicinity of clouds, we find a “reddening” of aerosols in the MODIS 500-m-resolution aerosol retrievals near clouds. This “reddening” in our study can be traced to larger absolute increases in SWIR reflectances when compared to visible reflectances near clouds, which in turn seem to stem from larger electronic cross talk in the MODIS SWIR bands (5–7). We note that the lack of “bluing” in our MODIS observations is likely due to the small geometric and optical thicknesses of the clouds considered.
Soil fertility as a parameter in land evaluation of moorland, Waldridge Fell, County Durham

The aim of these investigations is to assess the importance of soil fertility as a parameter in land evaluation of moorland. Waldridge Fell of County Durham is chosen as a specific reference, and the thesis comprises three parts:- I. General background to the problem, II. The environment of Waldridge Fell and III. Investigations and implications. Part I indicates the contemporary land use in Britain and its relation to the potential of moorland. The present land capability classification of County Durham and Waldridge Fell is reviewed and the approaches to the assessment of biological production in land evaluation are discussed. There follows a resume of moorland soils, and the influence of grazing and afforestation on them. Part II outlines the environmental background of Waldridge Fell, including a detailed description of the study site. The vegetation pattern and the correlated edaphic and biotic variables of the area are analysed in detail. Part III consists of experimental work and its implications. Environmental monitoring, from Nov. I970 - June 1972 was undertaken to investigate the seasonal fluctuations of soil fertility and biological yields of Calluna as affected by the weather conditions. A further assessment of different soils from the research area was undertaken in the laboratory. This leads to conclusions relating to the factors regulating productivity of Calluna in the field. The last chapter integrates soil fertility and the biological productivity assessment in land evaluation. Further analyses were carried out to test the interrelationships between the nutrient contents both in the soils and Calluna tissues, the effects of climate and the productivity of Calluna. The possibility of using soil chemical nutrients as parameters in predicting yield is also discussed.
Transient eddy formation around headlands

Eddies with length scales of 1–10 km are commonly observed in coastal waters and play an important role in the dispersion of water-borne materials. The generation and evolution of these eddies by oscillatory tidal flow around coastal headlands is investigated with analytical and numerical models. Using shallow water depth-averaged vorticity dynamics, eddies are shown to form when flow separation occurs near the tip of the headland, causing intense vorticity generated along the headland to be injected into the interior. An analytic boundary layer model demonstrates that flow separation occurs when the pressure gradient along the boundary switches from favoring (accelerating) to adverse (decelerating), and its occurrence depends principally on three parameters: the aspect ratio [b/a], where b and a are characteristic width and length scales of the headland; [H/CDa], where H is the water depth, CD is the depth-averaged drag coefficient; and [Uo/σa], where Uo and σ are the magnitude and frequency of the far-field tidal flow. Simulations with a depth-averaged numerical model show a wide range of responses to changes in these parameters, including cases where no separation occurs, cases where only one eddy exists at a given time, and cases where bottom friction is weak enough that eddies produced during successive tidal cycles coexist, interacting strongly with each other. These simulations also demonstrate that in unsteady flow, a strong start-up vortex forms after the flow separates, leading to a much more intense patch of vorticity and stronger recirculation than found in steady flow.
On the rank of random matrices over finite fields

A novel lower bound is introduced for the full rank probability of random finite field matrices, where a number of elements with known location are identically zero, and remaining elements are chosen independently of each other, uniformly over the field. The main ingredient is a result showing that constraining additional elements to be zero cannot result in a higher probability of full rank. The bound then follows by "zeroing" elements to produce a block-diagonal matrix, whose full rank probability can be computed exactly. The bound is shown to be at least as tight and can be strictly tighter than existing bounds.
Dielectric-Branes

We extend the usual world-volume action for a Dp-brane to the case of N coincident Dp-branes where the world-volume theory involves a U(N) gauge theory. The guiding principle in our construction is that the action should be consistent with the familiar rules of T-duality. The resulting action involves a variety of potential terms, i.e., nonderivative interactions, for the nonabelian scalar fields. This action also shows that Dp-branes naturally couple to RR potentials of all form degrees, including both larger and smaller than p+1. We consider the dynamics resulting from this action for Dp-branes moving in nontrivial background fields, and illustrate how the Dp-branes are ``polarized'' by external fields. In a simple example, we show that a system of D0-branes in an external RR four-form field expands into a noncommutative two-sphere, which is interpreted as the formation of a spherical D2-D0 bound state.
Sharks, Rays and A Chimaeroid from the Kimmeridgian (Late Jurassic) of Ringstead, Southern England

Sampling of a lenticular concentration of vertebrate debris and associated sediments from the lower Kimmeridgian of southern England has allowed the study of a diverse and abundant assemblage of chondrichthyan remains. A number of previously undescribed species are recorded, of which three new species are named; Squatina? frequens, Synechodus plicatus and Protospinax planus. Additional diagnosis of the genus Paracestracion Koken is given to allow its identification from dental remains. Several nominal batoid species are synonymised with Spathobatis bugesiacus Thiolliere. This assemblage is considered to be typical of Middle–Late Jurassic neritic environments, and is compared to other contemporaneous selachian faunas.
The Low-Frequency Variability of the Tropical Atlantic Ocean

Abstract Upper-ocean temperature variability in the tropical Atlantic is examined from the Comprehensive Ocean–Atmosphere Data Set (COADS) as well as from an ocean model simulation forced by COADS anomalies appended to a monthly climatology. The findings are as follows: Only the sea surface temperatures (SST) in the northern Tropics are driven by heat fluxes, while the southern tropical variability arises from wind-driven ocean circulation changes. The subsurface temperatures in the northern and southern Tropics are found to have a strong linkage to buoyancy forcing changes in the northern North Atlantic. Evidence for Kelvin-like boundary wave propagation from the high latitudes is presented from the model simulation. This extratropical influence is associated with wintertime North Atlantic oscillation (NAO) forcing and manifests itself in the northern and southern tropical temperature anomalies of the same sign at depths of 100–200 m as result of a Rossby wave propagation away from the eastern boundary i.
VARIATION OF ELASTIC MODULI OF IGNEOUS ROCKS WITH PRESSURE AND TEMPERATURE

Using pulse methods recently developed, direct measurements of the dilatational and rotational elastic wave velocities in igneous rocks were made. D. C. pulses, impressed on 5 MC X-cut piezoelectric quartz crystals, were used to excite sharp, elastic pulses in rocks. The amplified output of similar detector crystals was studied and photographed using suitable oscilloscopes. Two main arrivals of energy were precisely timed, and from the travel times the dilatational and elastic velocities were computed. Velocities were measured with an accuracy greater than 1 per cent. Regarding rocks as homogeneous, isotropic media, the elastic constants were computed from the velocity data. The sample assembly was placed in a pressure cell, surrounded by an oil bath; thus measurements at high pressures and temperatures could readily be made. Measurements were made in the pressure range 1–1100 kg. /cm. 2 and the temperature range 30–150°C. Samples of granite, quartz monzonite, diorite, andesite, and norite were investigated. Materials were studied both while enclosed in impervious copper jackets and while exposed to the fluid pressure medium. The enclosed samples had relatively great increases of velocity with pressure at the low pressures, presumably due to closing of initial pore space; the rate of increase became small and essentially linear at higher confining pressures. Open samples had small, linear rates of increase of velocity over the entire pressure range. Pressure increase was accompanied by increase of wave velocities and elastic constants in all cases. Increase of temperature was accompanied by decrease in velocities and moduli. Changes of Poisson9s ratio with pressure and temperature were small and erratic. The reasonably good agreement of the present work at effective frequencies of 2–6 megacycles with earlier measurements at low frequencies suggests that for rocks the effect of frequency upon velocity is negligible, although the data are, as yet, inconclusive. The present work has established a useful method of obtaining direct measurements of elastic wave velocities in rocks. Extension of the pressure and temperature ranges should provide data valuable for comparison with earthquake seismic results for the earth9s crust.
Manganite, Hausmannite, Braunite; Features, Modes of Origin

This paper is concerned with three of the fairly common, manganese oxide minerals, manganite, hausmannite, and braunite. The study includes the precise determination of the minerals: (1) by X-ray diffraction and (2) spectrographic analyses. Most of the numerous specimens were collected by the writer and associates on the U. S. Geological Survey at localities in the United States, supplemented by other specimens from wellknown localities elsewhere, especially Canada and Mexico. Following determinations of the minerals, the geological environment of the specimens was reviewed in the hope of making confident interpretations of their modes of origin. In many descriptions of the minerals, even during recent years, it has seemed that their identities have not been positively determined and the criteria by which the modes of origin are interpreted leave some doubt that conclusions are correct.The present review indicates confidently that hausmannite is hypogene although recently, hausmannite from several localities has been interpreted as supergene. In those places where the geologic environment is here reviewed, the conclusion of supergene origin is open to question. On the other hand, specimens of manganite and braunite examined seem to fall readily into two groups: (1) a group in which manganite and braunite are clearly hypogene and (2) a group in which these minerals are clearly supergene. In other words, both manganite and braunite can be formed either by deposition from solutions rising from depth or by descending solutions of surficial origin. Concerning braunite, it should be noted that it is not only abundant but is the dominant oxide in deposits that have been subjected to intense metamorphism; i.e., many deposits in India.
Effects of digital elevation model map scale and data resolution on a topography‐based watershed model

The effects of digital elevation model (DEM) map scale and data resolution on watershed model predictions of hydrologic characteristics were determined for TOPMODEL, a topography-based watershed model. The effects of topography on watershed hydrology are represented in TOPMODEL as the distribution of ln (a/tan B), where ln is the Napierian logarithm, a is the upslope area per unit contour length, and tan B is the gravitational gradient. The minimum, maximum, mean, variance, and skew values of the ln (a/tan B) distribution were computed from 1:24,000-scale (24K) DEMs at 30- and 90-m resolutions and from 1:250,000-scale (250K) DEMs at 90-m resolution for 71 areas in Pennsylvania, New York, and New Jersey. An analysis of TOPMODEL showed that model predictions of the depth to the water table, the ratio of overland flow to total flow, peak flow, and variance and skew of predicted streamflow were affected by both the DEM map scale and data resolution. Further TOPMODEL analyses showed that the effects of DEM map scale and data resolution on model predictions were due to the sensitivity of the predictions to the mean of the ln (a/tan B) distribution, which was affected by both DEM map scale and data resolution. DEM map scale affected the mean of the ln (a/tan B) distribution through its influence on the mean of the ln (a) distribution, which characterizes land-surface shape, and the mean of ln (1/tan B) distribution, which characterizes land-surface slope. DEM resolution, in contrast, affected the mean of the ln (a/tan B) distribution primarily by its influence on the mean of the ln (a) distribution.
Observation of and evidence for decays

Measurements of the branching fractions of → ± ∓ B K K * s and π → ± ∓ B K* s decays are performed using a data sample corresponding to − 1.0 fb 1 of protonproton collision data collected with the LHCb detector at a centre-of-mass energy of 7 TeV, where the ± K* mesons are reconstructed in the π± KS final state. The first observation of the → ± ∓ B K K * s decay and the first evidence for the π → − + B K* s decay are reported with branching fractions   π → = ± ± ×
Approximating the MaxCover Problem with Bounded Frequencies in FPT Time

We study approximation algorithms for several variants of the MaxCover problem, with the focus on algorithms that run in FPT time. In the MaxCover problem we are given a set N of elements, a family S of subsets of N, and an integer K. The goal is to find up to K sets from S that jointly cover (i.e., include) as many elements as possible. This problem is well-known to be NP-hard and, under standard complexitytheoretic assumptions, the best possible polynomial-time approximation algorithm has approximation ratio (1 − 1 ). We first consider a variant of MaxCover with bounded element frequencies, i.e., a variant where there is a constant p such that each element belongs to at most p sets in S. For this case we show that there is an FPT approximation scheme (i.e., for each β there is a β-approximation algorithm running in FPT time) for the problem of maximizing the number of covered elements, and a randomized FPT approximation scheme for the problem of minimizing the number of elements left uncovered (we take K to be the parameter). Then, for the case where there is a constant p such that each element belongs to at least p sets from S, we show that the standard greedy approximation algorithm achieves approximation ratio exactly 1 − e −max(pK/kSk,1) . We conclude by considering an unrestricted variant of MaxCover, and show approximation algorithms that run in exponential time and combine an exact algorithm with a greedy approximation. Some of our results improve currently known results for MaxVertexCover.
Optimal control of a non-smooth quasilinear elliptic equation

This work is concerned with an optimal control problem governed by a non-smooth quasilinear elliptic equation with a nonlinear coefficient in the principal part that is locally Lipschitz continuous and directionally but not G\^ateaux differentiable. This leads to a control-to-state operator that is directionally but not G\^ateaux differentiable as well. Based on a suitable regularization scheme, we derive C- and strong stationarity conditions. Under the additional assumption that the nonlinearity is a PC^1 function with countably many points of nondifferentiability, we show that both conditions are equivalent. Furthermore, under this assumption we derive a relaxed optimality system that is amenable to numerical solution using a semi-smooth Newton method. This is illustrated by numerical examples.