bluuebunny/crossref_metadata_2025_split huggingface dataset:
Measuring facial action
Authors: Cohn Jeffrey F , Ekman Paul 
Published: November 2023

Abstract
Of all the nonverbal behaviors—body movements, posture, gaze, proxemics, voice— the face is probably the most commanding and complicated, and perhaps the most confusing. In part, the face is commanding because it is always visible, always providing some information. There is no facial equivalent to the concealment maneuver of putting one’s hands in one’s pockets. Whereas sounds and the body movements that illustrate speech are intermittent, the face, even in repose, may provide information about some emotion or mood state. Many nonverbal behaviors simply do not occur when a person is alone, or at least do so very rarely.
Weak Solutions For Steady Navier–Stokes Equations Of Compressible Barotropic Flow
Authors: Novotný A , Straškraba I 
Published: November 2023

Abstract
This chapter is devoted to the weak solvability of steady compressible Navier– Stokes equations in the barotropic regime in different geometrical situations. After the formulation of the problem and the main statements for bounded and exterior domains in the first section, we explain, in the second section, the main ideas of the proof, and in the third section, the way the original system is approximated. In Section 4.4 we investigate weak compactness of the effective viscous flux which is the main tool of the proofs.
Global Behavior Of Weak Solutions
Authors: Novotný A , Straškraba I 
Published: November 2023

Abstract
In this chapter the asymptotic behavior of weak solutions to problem (7.1.1), (7.1.2), (7.1.3), (7.1.5), (7.1.6), (7.1.7), as time tends to infinity will be investigated. The solution will be supposed to have the regularity as in Theorem 7.7. The corresponding theorem on asymptotic behavior (Theorem 8.1 below) will be formulated for a general pressure law p = p(ρ) satisfying a certain growth condition. The hypotheses are formulated so that we have generic coincidence of hypotheses assumed in known existence theorems and those assumed here. This allows us to have both the existence of a solution and its asymptotic behavior, unconditionally. For a discussion of the existence for general pressure laws (i.e. not necessarily γ-law p(ρ) = Cργ) see Sections 7.12.1.2 and 7.12.3.
Strong Solutions Of Nonsteady Compressible Navier–Stokes Equations
Authors: Novotný A , Straškraba I 
Published: November 2023

Abstract
In this chapter we prove a version of the global existence theorem for compressible Navier–Stokes equations assuming the initial data sufficiently small in suitable norms. We choose the equations of viscous barotropic flow (see Section 1.2.18) in three space dimensions as a relatively simple illustrative example rather than equations including temperature as is the case in the pioneering papers (Matsumura and Nishida, 1979) and (Matsumura and Nishida, 1980); cf. also (Valli, 1983). For many other versions we refer the reader to references given in comments at the end of this chapter (see Section 9.10).
Vassiliev Invariants and the Loop States in Quantum Gravity
Authors: Kauffman Louis H 
Published: November 2023

Abstract
This paper derives (at the physical level of rigor) a general switching formula for the link invariants defined via the Witten functional integral. The formula is then used to evaluate the top row of the corresponding Vassiliev invariants and it is shown to match the results of Bar-Natan obtained via perturbation expansion of the integral. It is explained how this formalism for Vassiliev invariants can be used in the context of the loop transform for quantum gravity.
Topological Field Theory as the Key to Quantum Gravity
Authors: Crane Louis 
Published: November 2023

Abstract
Motivated by the similarity between CSW theory and the Chern-Simons state for general relativity in the Ashtekar variables, we explore what a universe would look like if it were in a state corresponding to a 3d TQFT. We end up with a construction of propagating states for parts of the universe and a Hilbert space corresponding to a certain approximation. The construction avoids path integrals, using instead recombination diagrams in a very special tensor category.
BF Theories and 2-knots
Authors: Cotta-Ramusino Paolo , Martellini Maurizio 
Published: November 2023

Abstract
The assumption that large mammal hunting and scavenging are economically advantageous to hominid foragers is examined in the light of data collected among the Hadza of northern Tanzania. Hadza hunters disregard small prey in favour of larger forms (mean adult mass 40 kg). Here we report experimental data showing that hunters would reduce their mean rates if they included small animals in the array they target. Still, daily variance in large animal hunting returns is high, and the risk of failure correspondingly great, significantly greater than that associated with small game hunting and trapping. Sharing large kills reduces the risk of meatless days for big game hunters, and obviates the problem of storing large amounts of meat. It may be unavoidable if large carcasses cannot be defended economically against the demands of other consumers. If so, then large prey are common goods. A hunter may gain no consumption advantage from his own big game acquisition efforts. We use Hadza data to model this ‘collective action’ problem, and find that an exclusive focus on large game with extensive sharing is not the optimal strategy for hunters concerned with maximizing their own chances of eating meat. Other explanations for the emergence and persistence of this practice must be considered.
Some basic concepts and theorems of probability theory
Authors: Petrov Valentin V 
Published: November 2023

Abstract
This chapter contains a summary of some basic concepts and theorems of probability theory that are needed in the following chapters. The proofs of many statements are omitted; they can be found in the books of, among others, Chung [78], Feller [133], Gnedenko [146], Loèeve [256], Lukacs [257] and Shiryaev [424]. Some more specialized results that border on the basic facts are also presented here.
Solid State Phenomena
Authors: Karlsson Erik b. 
Published: November 2023

Abstract
Solid state physics is a complex area which needs a full arsenal of experimental techniques to uncover all its intriguing aspects. The present book presents selected results from a couple of methods where phenomena in solids are observed from points of view that fall somewhat outside the experimental mainstream, but have contributed with unique information to the understanding of magnetism, supercondivity, point defects in metals, surface and interface physics and the physics and chemistry of metal/hydrogen systems, in particular diffusion phenomena. The PAC and USR methods described here are based on the observations of local magnetic and electric fields and their dynamic behaviour by recording the spin motion of excited nuclei and implanted positive muons, respectively; another method utilizes the electrostatic interaction of protons for the study of metallic multilayers and their interfaces. The text is centered on the relevant physical problems rather than being method-oriented and puts the specific, and sometimes unique, information gained by the above mentioned methods into a general perspective.
The Optical Model
Authors: Fröbrich P , Lipperheide R 
Published: November 2023

Abstract
In Chapter I we introduced the optical potential in order to account for the loss of current in the elastic channel owing to the coupling to non-elastic channels. The treatment there was purely phenomenological. It was based on an analogy with optics, where a complex index of refraction fulfils the function of a scattering potential for light waves in the presence of absorption.
What is a Logical System?
Authors: Gabbay Dov M 
Published: November 2023

Abstract
There is an increasing demand from computer science, linguistics and philosophy for a variety of logical systems. This is prompted by the extensive applications of logic in theoretical computer science, artificial intelligence and logic programming. In these fields there is a growing need for a diversity of semantically meaningful and algorithmically presented logical systems which can serve various applications. Therefore renewed research activity is being devoted to analysing and tinkering with old and new logics.
The Method of Hypersequents in the Proof Theory of Propositional Non-classical Logics
Authors: Avron Amon 
Published: November 2023

Abstract
Until not too many years ago, all logics except classical logic (and, perhaps, intuitionistic logic too) were considered to be things esoteric. Today this state of affairs seems to have been completely changed. There is a growing interest in many types of nonclassical logics: modal and temporal logics, substructural logics, paraconsistent logics, non-monotonic logics-the list is long. The diversity of systems that have been proposed and studied is so great that a need is felt by many researchers to try to put some order in the present logical jungle. Thus [Cleave, 1991], [Epstein, 1990] and [Wojcicki, 1988] are three recent books in which an attempt is made to develop a general theoretical framework for the study of logics. On the more pragmatic side, several systems have been developed with the goal of providing a computerized logical framework in which many different logical systems can be implemented in a uniform way. An example is the Edinburgh LF [Harper et al., 1993].
Subalgebras of Cohen Algebras Need Not be Cohen
Authors: Koppelberg Sabine , Shelah Saharon 
Published: November 2023

Abstract
Let us denote by CK the standard Cohen algebra of 7r-weight K, i.e. the complete Boolean algebra adjoining”‘ Cohen reals, where K is an infinite cardinal or 0. More generally, we call a Boolean algebra A a Cohen algebra if (for technical convenience in Theorems 0.3 and 0.4 below) it satisfies the countable chain condition and forcing with A (more precisely with the partial ordering A\ (O) is equivalent to Cohen forcing, i.e. if every generic extension of the universe of set theory arising from forcing with A arises from forcing with some standard Cohen algebra. Since forcing with an arbitrary Boolean algebra is equivalent to forcing with its completion and forcing with a product of algebras is equivalent to forcing with one of the factors, an algebra is Cohen iff its completion is isomorphic to a product of at most countably many standard Cohen algebras; we will use this description as the definition of a Cohen algebra in the rest of the paper.
Independence Structures in Set Theory
Authors: Lambalgen Michiel van 
Published: November 2023

Abstract
The axioms for ‘independent choices’ presented in [Lambalgen, 1992) are strengthened here, so that they can be seen as introducing a new type of indiscernibles in set theory. The resulting system allows for the construction of natural inner models. The article is organised as follows. Section 1 introduces the axioms, some preliminary lemmas are proved and the relation with the axiom of choice is investigated. Section O gives a philosophical motivation for the axioms; the reader who is not interested in such matters can skip this part. In section 2 we compare the structure introduced by the axioms, here called an independence structure, with two constructions from model theory, indiscernibles and minimal sets. Section 3 contains the construction of inner models, while section 4 presents some concluding philosophical remarks.
From Logic Programs to Inductive Definitions
Authors: Stark Robert F 
Published: November 2023

Abstract
The three-valued Fitting/Kunen semantics is one of the best declarative semantics for negation as failure in logic programming. We show that the three-valued consequences of the completion of a logic program are exactly the four-valued consequences of the completion. Since a four-valued relation can be represented by two two-valued relations, the four-valued completion semantics, and hence the three-valued Fitting/Kunen semantics, can be expressed in terms of classical consequences of an appropriate theory, which we call the partial completion of a logic program. We prove that SLDNF resolution is sound and complete with respect to the partial completion for a large class of normal logic programs, covering most programs of practical interest. This result can even be extended to SLDNF-resolution with builtin predicates. The partial completion, which is always consistent, leads in a natural way to formal theories of inductive definitions. We argue that such theories are appropriate for verification and termination proofs of logic programs.
Methods for the Multiple-Scattering
Authors: Molisch Andreas F , Oehry Bernhard P 
Published: November 2023

Abstract
For the multiple-scattering (MS) representation, we have to solve for the probability that a photon escapes after suffering i absorption/reemisison processes.9 For this computation, we have two possible approaches: Monte Carlo simulations, which have been used for 30 years, and analytical methods (Wiorkowski 1988), (Wiorkowski and Hartmann 1988), (Falecki et al. 1989, 1991). A Monte Carlo (MC) simulation is a very general, purely numerical algorithm for the modelling of complex physical processes. In the case of radiation trapping, it means tracing one photon after the other on its path through the vapour (House and Avery 1969), (Avery and House 1968). The photon’s emission frequency, direction, and path length before reabsorption are taken at random, according to the appropriate probability distributions. This means that the numbers are taken at random, but in such a way that they fulfil the statistics of the described physical process.
Simulation of optically pumped gas lasers
Authors: Molisch Andreas F , Oehry Bernhard P 
Published: November 2023

Abstract
The invention of the laser in the early 1960s has completely changed not only optics, but also all other sciences where light is required for experiments. This is especially true for atomic and molecular spectroscopy, but also for such diverse fields as remote sensing, material processing, and astronomy. Most of the millions of lasers currently in use around the world are semiconductor lasers (by far the largest group, due to their applications in consumer electronics and data storage) or solid state lasers with a crystalline host. Gas lasers are in use for special applications, where they cannot be replaced by solid-state lasers yet.
The Callan-Symanzik equations
Authors: Bellac Michel Le , Barton G 
Published: November 2023

Abstract
In Chapter 3 we met the word ‘renormalization’ through the expression ‘renor malization group’; recall that our strategy was to follow the evolution of the parameters defining the Hamiltonian through successive contractions of the cutoff &aiming to obtain the long-distance &1/A) behaviour of the theory. By contrast, the last chapter seemed to feature renormalization in the completely different context of eliminating a nonphysical (i.e. not directly applicable) bare theory in favour of a renormalized theory depending on just a few parameters. But we can observe already at this point that the renormalized theory, being finite as &-oo, is approximately independent of &when &is large but still finite; at least this is so in the long-distance region &l/ &Therefore one may hope to find a connection between the theory found by integrating over short-wavelength fluctuations, and the renormalized theory: both can be characterized as theories for long distances.
Path integrals in quantum and in statistical mechanics
Authors: Bellac Michel Le , Barton G 
Published: November 2023

Abstract
This chapter links Parts I and II, which were devoted to statistical mechanics, and Part III, which deals with quantum field theory. In Part III we shall revert to the tools developed for studying critical phenomena, namely functional integrals (often called path integrals in this new connection); Feynman diagrams; renormalization; and the renormalization group. A few adaptations are all that these tools need in their new context, and we shall use some elementary examples to illustrate the links between problems in statistical and in quantum mechanics.
Quantization of the Klein-Gordon field
Authors: Bellac Michel Le , Barton G 
Published: November 2023

Abstract
Quantum field theory was born of the need to describe processes where particles are created or destroyed (annihilated). One elementary example is the radiative transition of an atom from an excited state &to the ground state &emitting a photon (y): &+ &+ &+ &Reactions where particles are created or destroyed are basically different from chemical reactions, which correspond to rearrangements of the atoms within the molecules; and different also from nuclear reactions, where the nucleons redistribute themselves to yield new nuclei. In both cases there is rearrangement rather than creation or destruction. However, the distinction may not be as sharp as it seems, because the process of rearrangement can be quite complex, with (virtual) destruction or creation of particles in its intermediate stages. The Schroedinger equation, which assumes that the number of particles is fixed, cannot describe creation or annihilation processes; but already in the 1930s the founders of quantum mechanics discovered how this could be done through the quantization of classical fields (improperly called ‘second quantization’, for historical reasons).
Quantization of the Dirac field and of the electromagnetic field
Authors: Bellac Michel Le , Barton G 
Published: November 2023

Abstract
Modern elementary-particle physics is dominated by gauge theories, whose prototype is quantum electrodynamics (QED). The fundamental particles in such theories are These particles are assumed to be elementary, &In electrodynamics, the spin 1/2 particles are electrons (and their antiparticles, i.e. positrons), while the gauge particles are photons. In this case the interactions between spin 1/2 particles are mediated by photons: Fig. 11.1 shows a Feynman graph contributing to electron-electron scattering.
Enhanced information recovery in spectroscopy using the maximum entropy method
Authors: Davies S , Packer K J , Baruya A , Grant A I 
Published: November 2023

Abstract
The maximum entropy method for the reliable extraction of information from spectroscopic data is outlined. Examples are shown from Raman and nuclear magnetic resonance spectroscopies, with particular reference to the selection and parameterization of suitable lineshape functions for deconvolution. An account is also given of our experiences with a proposed definition of the entropy function different from the usual form.
Maximum entropy and plasma physics
Authors: Cottrell G A 
Published: November 2023

Abstract
Experiments on magnetically confined fusion plasmas, for example the Joint European Torus (JET) tokamak, require a range of diagnostic techniques for measurement of plasma quantities such as temperature and density. Usually, some kind of inverse transform is needed to convert measured raw signals into useful data. Also, there are often problems arising from inadequately sampled data and instrumental resolution limitations. It will be explained how the maximum entropy method (MaxEnt) can be applied in such cases with three advantages over conventional analysis: the generation of positive solutions, the suppression of noise and the suppression of spurious transform-related artefacts. MaxEnt is illustrated using a number of examples from the field, involving: the Fourier transform (for example, Michelson interferometry), deconvolution of spectra, and two-dimensional tomography of atomic beams. The advantages of MaxEnt are seen clearly in the problem of extracting the maximum amount of information, for example on plasma profiles, starting from only a limited and noisy data set. Used in this way, the method responds flexibly to the demands of the data and does not suppress any significant features.
The Measurement of Motion Using Spin Echoes
Authors: Callaghan Paul T 
Published: November 2023

Abstract
In Chapter 5 the concept of image contrast was introduced. The nuclear magnetic resonance spectrum is rich in details which reveal the molecular environment of the nucleus. Chemical shift contrast and other more sophisticated methods of spectral editing can provide molecularly selective images while other schemes take advantage of the various characteristic time-scales in NMR, giving effects which are highly sensitive to the motion of the surrounding molecule. For example, the use of relaxation time contrast can differentiate molecules via their characteristic rotational motions. The suggestion that nuclear magnetic resonance could be used to measure molecular translational motion dates from the earliest days of this field of research.
Pulsed NMR in solids-then and now
Authors: Slichter C P , Barrett S E , Becerra L , Durand D J , Klug C A , Martindale A , Pennington C H , Ross J H , Shore S , Wang Z , Zax D B 
Published: November 2023

Abstract
This volume celebrates the scientific career of Erwin Hahn. As a graduate student, he initiated pulsed NMR [1] . Immediately thereafter he discovered spin echoes [2]. I am one of the few practitioners of magnetic resonance still active who knew Erwin even before he made his celebrated discovery of spin echoes. The intervening years have seen a nearly complete transformation of magnetic resonance from steady state techniques to pulse methods. Pulse methods were employed heavily by physicists from the time of their discovery by Erwin, as is chronicled partially below. For the first 20 years of magnetic resonance, high resolution NMR as practised in chemistry labs employed steady state techniques. Indeed, a commercial pulsed NMR apparatus was not available. The discovery by Ernst and Anderson [3] that pulsed NMR could give high resolution results via Fourier transforms changed things, giving strong impetus to the use of pulse methods in chemistry. The final impetus was the discovery of the power of two-dimensional Fourier transforms to simplify spectra.
New angles in motional averaging
Authors: Samoson A , Sun B Q , Pines A 
Published: November 2023

Abstract
It is the dispersion of local magnetic fields-the spread of resonant frequencies inherent even in the simplest systems-that determines selectivity and resolution in NMR. The local fields among a group of coupled nuclei, for example, may be rendered non-stationary owing to spin flip-flops, or spin diffusion, and the associated resonance can acquire a certain width as a result. Another source of frequency dispersion arises from the dependence of most spin interactions on the orientation of the external magnetic field relative to each nucleus. Thus both the spin and spatial dependence of the magnetic interactions must be addressed if one is to realize full spectroscopic control in NMR. random molecular reorientation, spatial anisotropy is averaged largely to zero. For sufficiently rapid tumbling, only the isotropic components of the spin interactions remain and so it becomes possible to achieve truly high resolution. In solids, however, restrictions on molecular motion prevent the spins from sampling a spherically symmetric set of orientations. Here, there are two general solutions: either remove the field altogether, and by so doing eliminate the very notion of directionality, as in zero-field NMR (this eliminates also the distinct isotropic chemical shifts of different nuclei), or, alternatively, one can impose an artificial motion on the spins to create the equivalent of a spherically symmetric environment. This latter option, that of supplying the motion externally, was inherent in the spin echo experiment [1] and its generalizations [2] in which the spin angular momenta are perturbed while leaving the molecules in place; and in the sample-spinning experiments of Anderson [3] , in which the sample is rotated. Averaging in spin space has progressed from simple spin echoes to the prolonged trains introduced by Waugh and later workers for solids [4].