Miracle-dz/UniFAR-FTUs huggingface dataset:
The effects of mixing on tracer relationships in the polar vortices

We review recent analyses of tracer observations within the Arctic vortex, showing anomalous tracer-tracer relationships which indicate the mixing of outside air into the vortex. Similar anomalous relationships have previously been observed in vortex fragments, following breakdown of the Arctic vortex, and interpreted as indicative of mixing within the filamentary fragments. In the light of other observations we conclude that this interpretation is incorrect: the mixing took place into the vortex prior to breakdown. We discuss the effects of mixing on tracer relationships within the vortex, illustrated by results both from a simple conceptual model and from two three-dimensional chemical transport models. These models indicate that continuous mixing across the vortex edge produces entirely changed tracer relations inside the vortex and that separate, compact vortex relationships can develop. In general, tracer relationships should not be used to estimate denitrification or chemical ozone loss unless the effects of mixing can be quantified; this may be possible using information from other tracers, but one cannot assume that the effects of anomalous mixing are manifested as simple mixing lines on tracer-tracer diagrams.
Transient storage and downstream solute transport in nested stream reaches affected by beaver dams

Transient storage constitutes a key element in the hydrologic cycle of watersheds. Both in‐channel slow moving water (dead zones) and hyporheic zones can contribute to transient storage, which retains water and solutes, increases residence time and influences solute transport in streams. Beaver dams and other in‐stream obstructions throughout low‐order streams attenuate streamflow and provide dead zone storage in pools. In this article, we report the results of four tracer tests in nested stream reaches in Cherry Creek (Wyoming, USA) covering ∼2·5 km of stream length to explore how the degree of beaver dam obstructions and their impoundments influence water transient storage and downstream solute transport in low‐order streams in the Rocky Mountain region of the American West. Travel‐time parameters for the tracer tests increased linearly with beaver dam number (N) and pond size (V). Linear regression of the travel time to the peak concentration (Tp), the leading (Tl) and tailing edge (Tt) of the dye cloud and the duration of the dye cloud (Td) versus N and V were all significant (R2 = 0·99). Slopes of the linear regressions of Tt versus N and V, were three times larger than those for Tl, suggesting that longer residence times may be caused, in part, by transient storage in the stream system. One‐dimensional transport with inflow and storage (OTIS) modelled cross‐sectional area of transient storage zone (As) and dispersion coefficients (D) increased linearly with N and V and reach length. Two transient storage metrics, Fmean and $F_{\rm {med}}^{200}$, also showed a general increase with N and V, although the relationship was not as strong. This suggests that in‐channel dead zones associated with beaver dams provide opportunities for generating transient water storage. The linear relationship between dispersion coefficient and reach length suggests the dispersion process might be analogous to the hydrodynamic dispersion in groundwater settings. Copyright © 2009 John Wiley & Sons, Ltd.
A numerical modeling study of a Montana thunderstorm: 2. Model results versus observations involving electrical aspects

A recently developed Storm Electrification Model (SEM) has been used to simulate the July 19, 1981, Cooperative Convective Precipitation Experiment (CCOPE) case study cloud. This part of the investigation examines the comparison between the model results and the observations of the actual cloud with respect to its nonelectrical aspects. A timing equivalence is established between the simulation and observations based on an explosive growth phase which was both observed and modeled. This timing equivalence is used as a basis upon which the comparisons are made. The model appears to do a good job of reproducing (in both space and time) many of the observed characteristics of the cloud. These include: (1) the general cloud appearance; (2) cloud size; (3) cloud top rise rate; (4) rapid growth phase; (5) updraft structure; (6) first graupel appearance; (7) first radar echo; (8) qualitative radar range-height indicator evolution; (9) cloud decay; and (10) the location of hydrometers with respect to the updraft/-downdraft structure. Some features that are not accurately modeled are the cloud base height, the maximum liquid water content, and the time from first formation of precipitation until it reaches the ground. While the simulation is not perfect, the faithfulness of the model results to the observations is sufficient to give us confidence that the microphysical processes active in this storm are adequately represented in the model physics. Areas where model improvement is indicated are also discussed.
Self-Selective Correlation Ship Tracking Method for Smart Ocean System

In recent years, with the development of the marine industry, navigation environment becomes more complicated. Some artificial intelligence technologies, such as computer vision, can recognize, track and count the sailing ships to ensure the maritime security and facilitates the management for Smart Ocean System. Aiming at the scaling problem and boundary effect problem of traditional correlation filtering methods, we propose a self-selective correlation filtering method based on box regression (BRCF). The proposed method mainly include: 1) A self-selective model with negative samples mining method which effectively reduces the boundary effect in strengthening the classification ability of classifier at the same time; 2) A bounding box regression method combined with a key points matching method for the scale prediction, leading to a fast and efficient calculation. The experimental results show that the proposed method can effectively deal with the problem of ship size changes and background interference. The success rates and precisions were higher than Discriminative Scale Space Tracking (DSST) by over 8 percentage points on the marine traffic dataset of our laboratory. In terms of processing speed, the proposed method is higher than DSST by nearly 22 Frames Per Second (FPS).
Subspace Acceleration for Large-Scale Parameter-Dependent Hermitian Eigenproblems

This work is concerned with approximating the smallest eigenvalue of a parameter-dependent Hermitian matrix $A(\mu)$ for many parameter values $\mu$ in a domain $D\subset \mathbb{R}^P$. The design of reliable and efficient algorithms for addressing this task is of importance in a variety of applications. Most notably, it plays a crucial role in estimating the error of reduced basis methods for parametrized partial differential equations. The current state-of-the-art approach, the so-called successive constraint method (SCM), addresses affine linear parameter dependencies by combining sampled Rayleigh quotients with linear programming techniques. In this work, we propose a subspace approach that additionally incorporates the sampled eigenvectors of $A(\mu)$ and implicitly exploits their smoothness properties. Like SCM, our approach results in rigorous lower and upper bounds for the smallest eigenvalues on $D$. Theoretical and experimental evidence is given to demonstrate that our approach represents a sign.
Composition of the Martian dust as derived by infrared spectroscopy from Mariner 9

The Martian dust spectra obtained by the infrared interferometer spectrometer (Iris) experiment on Mariner 9 have been compared with modeling computations for various minerals and rocks. The model used was based upon a recently developed theory of absorption and scattering by particulate materials. The results indicate that the composition of Martian dust is biased toward silicate structures which involve a high degree of silicate oxygen sharing. A feldspar-rich dust of approximately 1-micron particle size appears to be the best candidate, although sheet-structure silicates cannot be ruled out.
Interference Cancellation at the Relay for Multi-User Wireless Cooperative Networks

We study multi-user transmission and detection schemes for a multi-access relay network (MARN) with linear constraints at all nodes. In a (J, Ja, Ra, M) MARN, J sources, each equipped with Ja antennas, communicate to one M-antenna destination through one Ra-antenna relay. A new protocol called IC-Relay-TDMA is proposed which takes two phases. During the first phase, symbols of different sources are transmitted concurrently to the relay. At the relay, interference cancellation (IC) techniques, previously proposed for systems with direct transmission, are applied to decouple the information of different sources without decoding. During the second phase, symbols of different sources are forwarded to the destination in a time division multi-access (TDMA) fashion. At the destination, the maximum-likelihood (ML) decoding is performed source-by-source. The protocol of IC-Relay-TDMA requires the number of relay antennas no less than the number of sources, i.e., Ra ≥ J. Through outage analysis, the achievable diversity gain of the proposed scheme is shown to be min {Ja (Ra - J + 1), RaM}. When M ≤ Ja(1- J-1/Ra), the proposed scheme achieves the maximum interference-free (int-free) diversity gain RaM. Since concurrent transmission is allowed during the first phase, compared to full TDMA transmission, the proposed scheme achieves the same diversity, but with a higher symbol rate.
Aspiration noise during phonation : synthesis, analysis, and pitch-scale modification

The current study investigates the synthesis and analysis of aspiration noise in synthesized and spoken vowels. Based on the linear source-filter model of speech production, we implement a vowel synthesizer in which the aspiration noise source is temporally modulated by the periodic source waveform. Modulations in the noise source waveform and their synchrony with the periodic source are shown to be salient for natural-sounding vowel synthesis. After developing the synthesis framework, we research past approaches to separate the two additive components of the model. A challenge for analysis based on this model is the accurate estimation of the aspiration noise component that contains energy across the frequency spectrum and temporal characteristics due to modulations in the noise source. Spectral harmonic/noise component analysis of spoken vowels shows evidence of noise modulations with peaks in the estimated noise source component synchronous with both the open phase of the periodic source and with time instants of glottal closure. Inspired by this observation of natural modulations in the aspiration noise source, we develop an alternate approach to the speech signal processing aim of accurate pitch-scale modification. The proposed strategy takes a dual processing approach, in which the periodic and noise components of the speech signal are separately analyzed, modified, and re-synthesized. The periodic component is modified using our implementation of time-domain pitch-synchronous overlap-add, and the noise component is handled by modifying characteristics of its source waveform. Since we have modeled an inherent coupling between the original periodic and aspiration noise sources, the modification algorithm is designed to preserve the synchrony between temporal modulations of the two sources. The reconstructed modified signal is perceived to be natural-sounding and generally reduces artifacts that are typically heard in current modification techniques. Thesis Supervisor: Thomas F. Quatieri Title: Senior Member of Technical Staff, MIT Lincoln Laboratory Faculty of MIT Speech and Hearing Bioscience and Technology Program
Deriving winter wheat characteristics from combined radar and hyperspectral data analysis

The main objective of this study is to derive plant nitrogen (N) status and aboveground biomass via satellite remote sensing. To understand canopy spectral reflectance, the focus of the first part was set on the analysis of spectral signatures of winter wheat during its vegetation period under different N treatments. Spectral reflectance at different phenological stages, measured by a spectroradiometer (ASD HandHeld), is related to agronomy parameters like plant N, aboveground biomass and leaf area index (LAI). For this purpose, an extensive field survey was carried out in Huimin County in the North China Plain. For detection of plant N status of winter wheat and biomass on regional scale, hyperspectral (EO-1 Hyperion) and radar (Envisat ASAR) remote sensing data were obtained. First results of preprocessing of remote sensing data are presented in this contribution.
F & H Monopoles

Supersymmetric monopoles of the heterotic string theory associated with arbitrary non-negative number of the left moving modes of the string states are presented. They include H monopoles and their T dual partners F monopoles (ALE instantons). Massive F = H monopoles are T self-dual. Solutions include also an infinite tower of generic T duality covariant non-singular in stringy frame F&H monopoles with the bottomless throat geometry. The massless F = –H monopoles are invariant under combined T duality and charge conjugation converting a monopole into anti monopole. All F&H monopoles can be promoted to the exact supersymmetric solutions of the heterotic string theory since the holonomy group is the compact SO(9). The sigma models for M monopoles, which admit constant complex structures, have enhanced world-sheet supersymmetry: (4,1) in general and (4,4) for the left-right symmetric monopoles. The space-time supersymmetric GS light-cone action in monopole background is directly convertible into the world-sheet supersymmetric NSR action. E-mail: behrndt@qft2.physik. hu-berlin.de 2 E-mail: kallosh@physics.stanford. edu
Using Hoare logic in a process algebra setting

This paper concerns the relation between process algebra and Hoare logic. We investigate the question whether and how a Hoare logic can be used for reasoning about how data change in the course of a process when reasoning equationally about that process. We introduce an extension of ACP (Algebra of Communicating Processes) with features that are relevant to processes in which data are involved, present a Hoare logic for the processes considered in this process algebra, and discuss the use of this Hoare logic as a complement to pure equational reasoning with the equational axioms of the process algebra.
Entanglement entropy in causal set theory

Entanglement entropy is now widely accepted as having deep connections with quantum gravity. It is therefore desirable to understand it in the context of causal sets, especially since they provide in a natural manner the UV cutoff needed to render entanglement entropy finite. Formulating a notion of entanglement entropy in a causal set is not straightforward because the type of canonical hypersurface-data on which its definition typically relies is not available. Instead, we appeal to the more global expression given in Sorkin (2012 (arXiv:1205.2953)) which, for a Gaussian scalar field, expresses the entropy of a spacetime region in terms of the field’s correlation function within that region (its ‘Wightman function’ W(x,x′)). Carrying this formula over to the causal set, one obtains an entropy which is both finite and of a Lorentz invariant nature. We evaluate this global entropy-expression numerically for certain regions (primarily order-intervals or ‘causal diamonds’) within causal sets of 1 + 1 dimensions. For the causal-set counterpart of the entanglement entropy, we obtain, in the first instance, a result that follows a (spacetime) volume law instead of the expected (spatial) area law. We find, however, that one obtains an area law if one truncates the commutator function (‘Pauli–Jordan operator’) and the Wightman function by projecting out the eigenmodes of the Pauli–Jordan operator whose eigenvalues are too close to zero according to a geometrical criterion which we describe more fully below. In connection with these results and the questions they raise, we also study the ‘entropy of coarse-graining’ generated by thinning out the causal set, and we compare it with what one obtains by similarly thinning out a chain of harmonic oscillators, finding the same, ‘universal’ behaviour in both cases.
Realizing the potential of quarkonium

I recall the development of quarkonium quantum mechanics after the discovery of Υ. I emphasize the empirical approach to determining the force between quarks from the properties of cc and bb bound states. I review the application of scaling laws, semiclassical methods, theorems and near-theorems, and inverse-scattering techniques. I look forward to the next quarkonium spectroscopy in the Bc system.
Invariant operators on manifolds with almost Hermitian symmetric structures, I. Invariant differentiation

This is the first part of a series of papers. The whole series aims to develop the tools for the study of all almost Hermitian symmetric structures in a unified way. In particular, methods for the construction of invariant operators, their classification and the study of their properties will be worked out. In this paper we present the invariant differentiation with respect to a Cartan connection and we expand the differentials in the terms of the underlying linear connections belonging to the structures in question. Then we discuss the holonomic and non-holonomic jet extensions and we suggest methods for the construction of invariant operators.
Long-term annual manure applications increase soil organic matter and nitrogen, and decrease carbon to nitrogen ratio

The effects of long-term annual applications of cattle (Bos taurus) feedlot manure on the accumulation, decomposition (amounts and rates), and movement of organic matter (OM) and Kjeldahl-determined N (total N) in soil were determined. Manure was applied annually since 1973 at three different levels to nonirrigated and irrigated Dark Brown Chernozemic (Typic Haploborolls) clay loam soil. Significant increases in soil OM and total N content in the first 8 and 6 yr, respectively, as affected by the level of manure application, were limited to the surface 30 cm of soil of the nonirrigated and irrigated land. Tillage did not affect the amount of OM and total N accumulated in the soil, but it did affect their distribution within the 0 to 30-cm depth, which is attributed to placement during incorporation. The accumulation of OM and total N were similar under nonirrigated and irrigated conditions. Manure (C/N ratio of ca. 10.2) lowered the C/N ratio of the soil (ca. 8.2) by small amounts. The accumulation of OM and total N was described by a Michaelis-Menten type of function. A response surface was generated for the accumulation of OM and total N with increasing levels and years of manure application, from which the rates of accumulation and decomposition were derived. The rates of accumulation decrease with years of application such that after two or three decades increases will be small. The model can be used to develop general guidelines for use and disposal of feedlot manure under similar conditions.
Early Development of Karst Systems: 2. Turbulent Flow

A simulation model developed to explore patterns of fracture enlargement within incipient limestone karst aquifers has been extended to turbulent flow. In contrast to the highly selective passage enlargement that occurs early in cave network development under laminar flow, the transition to turbulent flow results in more general passage enlargement, leading to maze networks when initial fractures are large and hydraulic gradients are high. These results support previously published hypotheses for the development of maze patterns, including formation within structural settings that have created initially large fractures or within flow systems periodically inundated by flooding. Maze development is also favored under turbulent flow when passages are entirely water filled, and where the groundwater flow system is long-lived. By contrast, branched patterns are most common when passages become free-surface subterranean streams, because depression of the piezometric surface along main passages, downcutting along main passages, and possible infilling with sediment of side passages limit the sharing of discharge among interconnected fractures or bedding planes that promote maze development.
The Vredefort Ring: A Further Consideration

opposite shore of the Firth of Forth. Then it is merely necessary to accept that the simple ring faults seen at the surface of modern calderas are continued at depth (Wilshire's fig. 6, c, p. 480, would well serve to illustrate this if allowance is made for displacement at the neck margin). At the surface there is no reason why there should be any downturning of the bedding, but at depth, where the conduit or fault circumference contracts, the space problem is encountered. To supplement the diverse solutions which have already been advanced (Williams, 1941; Reynolds, 1956) I suggest that the problem is at least partly resolved by the observed downward dragging of the wall rocks and of the bedding inside the neck margins.
Temporal behavior of a solute cloud in a heterogeneous porous medium: 1. Point‐like injection

We investigate the temporal behavior of transport coefficients in a model for transport of a solute through a spatially heterogeneous saturated aquifer. In the framework of a stochastic approach we derive explicit expressions for the temporal behavior of the center‐of‐mass velocity and the dispersion of the concentration distribution after a point‐like injection of solute at time t=0, using a second‐order perturbation expansion. The model takes into account local variations in the hydraulic conductivity (which, in turn, induce local fluctuations in the groundwater flow velocities) and in the chemical adsorption properties of the medium (which lead to a spatially varying local retardation factor). In the given perturbation theory approach the various heterogeneity‐induced contributions can be systematically traced back to fluctuations in these quantities and to cross correlations between them. We analyze two conceptually different definitions for the resulting dispersion coefficient: the “effective”dispersion coefficient which is derived from the average over the centered second moments of the spatial concentration distributions in every realization and the “ensemble” dispersion coefficient which follows from the second moment of the ensemble‐averaged concentration distribution. The first quantity characterizes the dispersion in a typical realization of the medium, whereas the second one describes the (formal) dispersion properties of the ensemble as a whole. We give explicit analytic expressions for both quantities as functions of time and show that for finite times their temporal behavior is remarkably different. The ensemble dispersion coefficient which is usually evaluated in the literature considerably overestimates the dispersion typically found in one given realization of the medium. From our explicit results we identify two relevant timescales separating regimes of qualitatively and quantitatively different temporal behavior: The shorter of the two scales is set by the advective transport of the solute cloud over one disorder correlation length, whereas the second, much larger one, is related to the dispersive spreading over the same distance. Only for times much larger than this second scale, do the effective and the ensemble dispersion coefficient become equivalent because of mixing caused by the local transversal dispersion. The formulae are applied to the Borden experiment data. It is concluded that the observed dispersion coefficient matches the effective dispersion coefficient at finite times proposed in this paper very well.