bluuebunny/crossref_metadata_2025_split huggingface dataset:
Social Psychological Factors Related to the Study of Arabic Among Israeli High School Students
Authors: Kraemer Roberta 
Published: November 2008

This study investigated the generalizability of Gardner's socioeducational model for second language learning to a highly different social context from that in which the model was developed. Specifically, the study examined Jewish high school students in Israel learning Arabic as a foreign language in a setting characterized by a high degree of intergroup conflict. Four tenets were identified as forming the essential core of Gardner's theory. These we would expect to apply across widely differing contexts in order to support the generalizability of the model. Other elements in the model, as well as the degree of relationship between variables, may be specific to the social context. The main hypothesis posited an expanded version of Gardner's model that included additional constructs—both general and context specific.The subjects for this study were 484 pupils studying Arabic in the 10th grade in regular high school programs. The instruments consisted of written questionnaires that were administered during two regular class periods. Teachers' marks were collected at the end of the school year. The hypothesis was tested using linear structural relations (or LISREL) causal modeling techniques. Regarding each of the four core elements in Gardner's theory, we concluded that the model was indeed generalizable to the context of this study. Other relationships between variables in the model are interpreted in light of the specific language learning context.
On Explicit and Negative Data Effecting and AffectingCompetenceandLinguistic Behavior
Authors: Schwartz Bonnie D. 
Published: November 2008

Psychologically speaking, all linguistic behavior is the overt manifestation of some type of underlying knowledge that is represented in the mind/brain of an individual. Exposure to linguistic data is necessary forgrowthof the system of knowledge. On the basis of only overt linguistic behavior, how can we ascertain whether the native and nonnative knowledge systems that people have are of distinct or similar types? Is there a (necessary) relationship betweentype of knowledgeandtype of linguistic exposure?The hypothesis to be defended is that negative data and explicit data result in a type of knowledge that is not to be equated withlinguistic competence. The claim is not that negative and explicit data cannot give rise to knowledge; rather, the specific claim is that only positive data can effect the construction of aninterlanguage grammarthat is comparable to the knowledge system that characterizes the result of first language acquisition.
Developing Pragmatic Fluency in English as a Foreign Language:Routines and Metapragmatic Awareness
Authors: House Juliane 
Published: November 2008

This study explores whether pragmatic fluency can best be acquired in the classroom by provision of input and opportunity for communicative practice alone, or whether learners profit more when additional explicit instruction in the use of conversational routines is provided. It is hypothesized that such instruction raises learners' awareness of the functions and contextual distributions of routines, enabling them to become more pragmatically fluent.Two versions of a communication course taught to advanced German learners of English for 14 weeks are examined, one version providing explicit metapragmatic information, the other withholding it. Samples of tape-recorded conversations at various stages of the courses are used to assess how students' pragmatic fluency developed and whether and how the development of fluency benefits from metapragmatic awareness.
Lattice-valued random walks with Markov chain dependent steps
Authors: Daley D. J. 
Published: November 2008

AbstractThe probability of ever returning to the origin and the mean square displacement afternsteps are studied for some lattice-valued random walks, whose successive steps constitute a Markov chain on a finite state space with transition probabilities of a simple kind, and such that the returns to the origin form a regenerative phenomenon. The case of walks on a diamond lattice with no immediate reversals is included: this example is relevant as a polymer chain building model. The numerical evaluation of the return probabilities of some three-dimensional walks is discussed and examples given.
The law of the iterated logarithm for certain power series and generalized Nörlund methods
Authors: Kiesel Rüdiger 
Published: November 2008

AbstractLet (pn) be a sequence of real numbers with pn ~ R(n), R(.) a regulary varying function with index greater than −1/2. We prove the Hartman–Wintner law of the iterated logarithm for the corresponding (Jp) power series transform and generalized Nörlund transforms (Nβp) of sequences (Xn) of i.i.d. random variables with mean-zero and variance 1. We also identify the cluster sets.
The Meromorphisms of an Elliptic Function-Field
Authors: Davenport H. 
Published: November 2008

1. Hasse's second proof of the truth of the analogue of Riemann's hypothesis for the congruence zeta-function of an elliptic function-field over a finite field is based on the consideration of the normalized meromorphisms of such a field. The meromorphisms form a ring of characteristic 0 with a unit element and no zero divisors, and have as a subring the natural multiplications n (n = 0, ± 1, …). Two questions concerning the nature of meromorphisms were left open, first whether they are commutative, and secondly whether every meromorphism μ satisfies an algebraic equation
with rational integers n0, … not all zero. I have proved that except in the case (which is equivalent to |N−q|=2 √q, where N is the number of solutions of the Weierstrassian equation in the given finite field of q elements), both these results are true. This proof, of which I give an account in this paper, suggested to Hasse a simpler treatment of the subject, which throws still more light on the nature of meromorphisms. Consequently I only give my proof in full in the case in which the given finite field is the mod p field, and indicate briefly in § 4 how it generalizes to the more complicated case.
Transient Oscillations in a Loud-Speaker Horn
Authors: McLachlan N. W. , Mckay A. T. 
Published: November 2008

The steady state theory of sound propagation in exponential loud-speaker horns is well known. The problem of transients, however, has not been treated hitherto, so in this paper it is proposed to consider what happens when the air particles at the throat of the horn are suddenly set in motion. To avoid difficulties which arise in treating sound propagation in the horn when the linear dimensions of the cross-section are comparable with the wave-length of the sound, the followingartifice is postulated. The axis of the horn is linear and the air column is divided up into a large number of frictionless conduits by very thin rigid partitions as indicated in Fig. 1. The cross-section of each conduit expands exponentially from the throat towards the mouth of the horn. The major linear dimension of the section of a conduit at the mouth is small in comparison with the wave-length of the highest frequency to be reproduced.
A Remark on Fourier Transforms
Authors: Zygmund A. 
Published: November 2008

1. Let f(x) be a complex function belonging to LP (−∞, ∞); i.e. let f(x) be measurable, and |f(x)|p integrable, over (−∞, ∞). The functionis called the Fourier transform of f(x), if the integral on the right exists, in some sense, for almost every value of y. It is well known that, if 1 ≤ p ≤ 2, the integral (1) converges in mean, with index p′ = p/(p – l)† i.e. thatwhere
The circular plate condenser at small separations
Authors: Hutson V. 
Published: November 2008

AbstractThe problem considered is the oppositely charged, circular disk condenser when the disks are very close together. An integral equation due to Love(5) is used as the governing equation of the problem. This equation is solved asymptotically for small separations by splitting the field into regions, one being an annulus containing the edges, the other being the rest of the domain, and combining these solutions. Bounds for the error in the solution of the integral equation are obtained rigorously; the error is shown to approach zero as the separation approaches zero. The capacity of the system is deduced from this solution. The problem of finding the capacity has previously been attempted by various authors, whose results have differed. The present treatment establishes which of these results is correct.
Scattering of plane elastic waves at rough surfaces. II
Authors: Abubakar Iya 
Published: November 2008

AbstractThis is a continuation of (1) on the two-dimensional problem of the diffraction of elastic waves by irregular surfaces. The effect of an irregular surface with an isolated irregularity like a trough or ditch on incident plane harmonic P- and SV-waves is discussed. The maximum depth of the ditch is assumed small compared to the wavelength of the incident wave.It is found that, when either a P- or an SV-wave is incident on such a boundary, besides the specularly reflected P- and SV-waves whose amplitudes are independent of the curvature of the surface there exist scattered waves travelling in various directions. In particular the diffracted zone contains the following second wave-types whose amplitudes are proportional to the depth of the ditch: (i) direct reflected P- and SV-waves, which at large distances appear to diverge from the point of intersection of the axis of symmetry of the ditch and the horizontal plane asymptotic to the boundary if the ratio of the wavelength of the incident wave to the half-width of the ditch is large. If the ratio is small these waves are reflected in the specular directions, (ii) A ‘secondary S-wave’ which finishes as P having travelled most of the way as an SV-wave. Its energy is confined to the neighbourhood of the free surface, (iii) A secondary P-wave which travels along the surface and finally emerges into the medium as an SV-wave at the critical angle for the medium, (iv) Rayleigh waves whose particle motion is in elliptic orbits.
The solution of boundary value problems for a general hodograph equation
Authors: Mackie A. G. 
Published: November 2008

ABSTRACTIn this paper the solution is found of certain boundary value problems appropriate to the flow of an invisoid, compressible fluid past a wedge-shaped profile. The most general hodograph equation in the formis used. Expressions are found for the position coordinates and the drag. The resulting solutions are then discussed for functions k(σ) appropriate to Chaplygin's equation, Tricomi's equation and the equation of Tomotika and Tamada. The case of Helmholtz flow past a wedge with sonic velocity upstream is treated in detail, and the resulting expressions for the drag enable an estimate to be made of the error which results in using approximations to Chaplygin's equation.
Integrals developable about a singular point of a Hamiltonian system of differential equations. Part II
Authors: Cherry T. M. 
Published: November 2008

This paper completes an investigation, of which the first part has already been published, into the integrals of a Hamiltonian system which are formally developable about a singular point of the system. Letbe a system of differential equations of which the origin is a singular point of the first type, i.e. a point at which H is developable in a convergent Taylor series, but at which its first derivatives all vanish. We suppose that H does not involve t, and we consider only integrals not involving t. Let the exponents of this singular point be ± λ1, ± λ2,…±λn. In Part I, I considered the case in which the constants λ1,…λn are connected by no relation of commensurability, i.e. a relation of the formwhere A1…An are integers (positive, negative or zero) not all zero, and showed that the equations (1) possess n, and only n, integrals not involving t which are formally developable as power series in the xk, yk. In this paper I consider the case in which λ1 … λn are connected by one or more relations of commensur-ability. Suppose that there are p, and only p, such relations linearly independent (p > 0): it will be shown that the equations (1) possess (n − p) independent integrals not involving t, formally developable about the origin and independent of H.
The Determination of the Frequency of an Alternating Current Supply by the Vibrations of Rods
Authors: Searle G. F. C. 
Published: November 2008

One method of measuring frequency depends upon resonance. If a body of unit mass, subject to elastic constraints and experiencing a damping resistance proportional to its speed, be acted on by a periodic force F sin pt, the equation of motion may be writtenThe amplitude of the steady vibration ultimately set up isthe maximum value occurring when p2 = q2 − 2s2. If the motion, in the absence of the dri ving force F sin pt, be only slightly damped, s2 is very small compared with q2, and little error will be made if the value of p giving maximum amplitude be taken as equal to q. When s/q is small, the resonance is “sharp,” i.e. a small discrepancy between p and q, or, more strictly, between p and (q2 − 2s2)½, causes the amphtude to fall far below its maxìmum value. Thus, when the damping is small, maximum amplitude, f or variation of p, indicates that p is very nearly equal to q.
On a class of renewal functions
Authors: Daley D. J. 
Published: November 2008

Renewal processes in discrete time (or as they are commonly termed, recurrent events) are appropriately described byrenewal sequences{un} which aregeneratedby discrete distributions, according to the equationAny two renewal sequences {u′n}, {u″n} define another renewal sequence {un} by means of their term-by-term product {un} = {u′nu″n}, for the joint occurrence of two independent recurrent events ℰ′ and ℰ″ is also a recurrent event. Considering a renewal process in continuous time for which we shall suppose a frequency functionf(x) of the lifetime distribution exists, so that a renewal density exists, the analogous property would be that for two renewal density functionsh1(x) andh2(x), the functionh(x) =h1(x)h2(x) is a renewal density function. A little intuitive reflexion shows that whileh(x)dxhas a probability density interpretation, this is not in general true ofh1(x)h2(x)dx. It is not surprising therefore to find in example 1 a case where the product of two renewal densities is not a renewal density. Example 2, on the other hand, shows that in some cases it is true, and taken together with example 1, there is suggested the problem of characterizing the class of renewal densitiesh(x) for which αh(x) is a renewal density for all finite positive α and not merely α in 0 < α ≤A< ∞. In turn this characterization enables us to define a classof renewal densities for whichh1(x) andimply that.
The Propagation of Electromagnetic Waves in a Refracting Medium in a Magnetic Field
Authors: Hartree D. R. 
Published: November 2008

The equations of propagation of electromagnetic waves, simple harmonic in time, in an optically anisotropic stratified medium are obtained from the treatment of the refracted wave as the resultant of the incident wave and wavelets scattered by the elements of volume of the medium, and are reduced to a simple form.The primitive property of the medium, from which the other optical properties are derived, is the scattering tensor, relating the induced dipole moment per unit volume to the applied electric field.The relation between the dielectric tensor (corresponding to the dielectric constant of an isotropic medium) and the scattering tensor is obtained.A medium consisting of classical oscillators in an external magnetic field is then considered, the scattering tensor and dielectric tensor are evaluated for such a medium, and finally a formula for the refractive index is obtained.For an ionised medium the formula differs from that obtained by Goldstein; the difference is due to the inclusion in the present treatment of a term omitted by Goldstein; the significance of this term is discussed, and its inclusion justified.Taking this term into account makes an important difference to the properties of the medium for long waves; an example is given.
A Geometrical treatment of the Correspondence between Lines in Threefold Space and Points of a Quadric in Fivefold space
Authors: Turnbull H. W. 
Published: November 2008

§ 1. The six Plücker coordinates of a straight line in three dimensional space satisfy an identical quadratic relationwhich immediately shows that a one-one correspondence may be set up between lines in three dimensional space, λ, and points on a quadric manifold of four dimensions in five dimensional space, S5. For these six numbers pij may be considered to be six homogeneous coordinates of such a point.
On the representation of the modular group of order ½p (p2 – 1) as a group of linear substitutions on ½ (p – 1) symbols, ichen p is a prime of the form 4n + 3
Authors: Burnside W. 
Published: November 2008

The actual form of the set of linear substitutions on 3 symbols, which gives a representation of the simple group of order 168, has been known for many years.In these Proceedings (vol. 20, pp. 247–9) I have determined the form of the set of linear substitutions on 5 symbols which gives a representation of the simple group of order 660.
Energy problems in the continuous spectra of β-rays
Authors: Chalmers J. A. 
Published: November 2008

By their measurements on the heating effect of the β-rays of Radium E, Ellis and Wooster(1) have proved that the continuous spectra of β-rays represent the actual β-rays of disintegration. Since the β-rays in the continuous spectrum have a wide range of energies, there arise problems which can best be understood by considering a particular series of disintegrations, which we may regard as typical; the most suitable series to consider is the following:The main problem that arises is to reconcile the facts that the β-rays from Thorium B and Thorium C are emitted with a wide range of energies, while before, in Thorium A, and after, in Thorium C and Thorium C′, we have bodies which emit α-rays which are homogeneous, or, at most, consist of a few homogeneous groups [Rosenblum(2)].
The Wave Mechanics of an Atom with a Non-Coulomb Central Field. Part I. Theory and Methods
Authors: Hartree D. R. 
Published: November 2008

The paper is concerned with the practical determination of the characteristic values and functions of the wave equation of Schrodinger for a non-Coulomb central field, for which the potential is given as a function of the distance r from the nucleus.The method used is to integrate a modification of the equation outwards from initial conditions corresponding to a solution finite at r = 0, and inwards from initial conditions corresponding to a solution zero at r = ∞, with a trial value of the parameter (the energy) whose characteristic values are to be determined; the values of this parameter for which the two solutions fit at some convenient intermediate radius are the characteristic values required, and the solutions which so fit are the characteristic functions (§§ 2, 10).Modifications of the wave equation suitable for numerical work in different parts of the range of r are given (§§ 2, 3, 5), also exact equations for the variation of a solution with a variation in the potential or of the trial value of the energy (§ 4); the use of these variation equations in preference to a complete new integration of the equation for every trial change of field or of the energy parameter avoids a great deal of numerical work.For the range of r where the deviation from a Coulomb field is inappreciable, recurrence relations between different solutions of the wave equations which are zero at r = ∞, and correspond to terms with different values of the effective and subsidiary quantum numbers, are given and can be used to avoid carrying out the integration in each particular case (§§ 6, 7).Formulae for the calculation of first order perturbations due to the relativity variation of mass and to the spinning electron are given (§ 8).The method used for integrating the equations numerically is outlined (§ 9).
The Wave Mechanics of an Atom with a Non-Coulomb Central Field. Part II. Some Results and Discussion
Authors: Hartree D. R. 
Published: November 2008

The methods of solution of the wave equation for a central field given in the previous paper are applied to various atoms. For the core electrons, the details of the interaction of the electrons in a single nk group are neglected, but an approximate correction is made for the fact that the distributed charge of an electron does not contribute to the field acting on itself (§2).For a given atom the object of the work is to find a field such that the solutions of the wave equation for the core electrons in this field (corrected as just mentioned for each core electron) give a distribution of charge which reproduces the field. This is called the self-consistent field, and the process of finding it is one of successive approximation (§ 3).Approximations to the self-consistent field have been found for He (§ 4), Rb+ (§ 5), Na+, Cl− (§ 9). For He the energy parameter for the solution of the wave equation for one electron in the self-consistent field of the nucleus and the other corresponds to an ionisation potential of 24·85 volts (observed 24·6 volts); this agreement suggests that for other atoms the values of the energy parameter in the self-consistent field (corrected for each core electron) will probably give good approximations to the X-ray terms (§4).The most extensive work has been carried out for Rb+. The distribution of charge given by the wave functions in the self-consistent field is compared with the distribution calculated by other methods (§ 6). The values of X-ray and optical terms calculated from the self-consistent field show satisfactory agreement with those observed (§ 7).The wave mechanical analogue of the case in which on the orbital model an internal and an external orbit of the same energy are possible is discussed (§ 8).
The stability of a strut under thrust, when buckling is resisted by a force proportional to the displacement
Authors: Goldstein S. 
Published: November 2008

For a strut under thrust when buckling is resisted by a force proportional to the displacement, it is shown that for both a clamped and a pinned strut there is stability for any length when the thrust is less than a certain critical value; and the relation is found between the length and the first value of the thrust above this that will give buckling. A notion of the wave-length and number of nodes after buckling is obtained.The results are applied to the theory of the formation of mountains by horizontal compression, and it is shown that the crust of the earth would be able to transmit, without buckling, stresses right up to the breaking stress across regions of continental extent, unless the depth down to the level of no strain were less than 16 metres.An attempt is made to employ the results also to consider the stability of solid surface films under compression, and it is seen that other factors, making for stability, must enter besides rigidity and gravity. This is supplied by surface tension, and it then appears that collapse due to a weakness in the film must precede buckling.A rough calculation is given of the frequency of vibration of an atom in a solid film.
On the annihilation radiation of the positron
Authors: Klemperer Otto 
Published: November 2008

Boron and carbon activated by diplon and proton bombardment have been used as positron emitting sources in experiments on the annihilation radiation.By coincidence counting with two Geiger-Müller tubes it has been established that the radiation is emitted in pairs.By the coincidence method of Becker and Bothe it has been shown that the annihilation radiation consists only of “soft” quanta.By ordinary absorption measurements it has been shown that the annihilation radiation is homogeneous with a hardness corresponding to 0·5 million e-volt.