bluuebunny/crossref_metadata_2025 huggingface dataset:
Acid modified bamboo‐type carbon nanotubes and cup‐stacked‐type carbon nanofibres as adsorbent materials: cadmium removal from aqueous solution
Authors: Andrade‐Espinosa Guillermo , Muñoz‐Sandoval Emilio , Terrones Mauricio , Endo Morinobu , Terrones Humberto , Rangel‐Mendez J Rene
Published: November 2008

BACKGROUND: Nitrogen‐doped multi‐walled carbon nanotubes (CNx) and cup‐stacked‐type carbon nanofibres (CST) were modified with nitric acid, at 85 °C, for 1–3 h to enhance their cation adsorption capacity, and were used for cadmium removal from aqueous solutions. These carbon nanostructures were characterized by SEM, EDX, FTIR, BET surface area, TGA and acid/base titrations. In addition, cadmium adsorption experiments were carried out at different pH values and constant temperature.

RESULTS: EDX and FTIR revealed a 0.4 times increase in oxygen content after acid treatment, which was reflected in an increment of up to 1.93 mmol g−1 of acid sites and in a shift of about two units of the zero point charge to lower pH values. The BET surface area, in general, decreased as the oxidation time increased. Finally, batch sorption experiments indicated that CNx are more effective than CST to sequester Cd2+ at pH 7; the sorption capacities of these materials increased as pH rose.

CONCLUSIONS: The results obtained indicate that it is feasible to modify both physical and chemical properties of the carbon nanostructures CNx and CST by HNO3 in such a way that they can be used to adsorb cations present in aqueous solutions. Copyright © 2008 Society of Chemical Industry
Maturity‐related chilling tolerance in mango fruit and the antioxidant capacity involved
Authors: Zhao Zhilei , Cao Jiankang , Jiang Weibo , Gu Yuhong , Zhao Yumei
Published: November 2008

BACKGROUND: In order to evaluate how effect of mature stage on the chilling tolerance of mangoes (Mangifera indica L. cv. ‘Zihua’) and the mechanism involved, the fruit were categorized into three stages of ripeness: Green (100% green fruit), Preyellow (10–20% yellow fruit) and Yellow (45–55% yellow fruit) after harvest and stored at 2 °C for 12 days and then incubated at 25 °C for 2 days for chilling injury (CI) development.

RESULTS: CI index in Preyellow and Yellow fruit was significantly lower than that of the Green fruit, as a rapid increase in ion leakage was observed in the Green fruit. Activities of superoxide dismutase, catalase, ascorbate peroxidase and polyphenoloxidase of Preyellow and Yellow fruit were higher than those of the Green from day 6 to day 12 during cold storage. A lower content of malondialdehyde but higher levels of glutathione and ascorbic acid were maintained in Preyellow and Yellow fruit than that in Green fruit.

CONCLUSION: These results suggested that stronger resistance of Preyellow and Yellow mangoes to CI compared to Green fruit was due to their higher antioxidant capacity involved in the tolerance to chilling temperature. Alleviating CI in mangoes during storage may be achieved by storing the fruit when skin colour is beginning to change to yellow from green. Copyright © 2008 Society of Chemical Industry
Consuming Lattes and Labor, or Working at Starbucks
Authors: Simon Bryant
Published: November 2008

This is an ethnographic portrait of working at one of the most conspicuous components of the neoliberal order: the upscale looking, fast-food acting coffee chain, Starbucks. Simon discusses the emotional labors of being a happy and chatty “partner” (employee), the difficulties of the uneven scheduling, the unexpected physical aspects of the job, and the culture of conformity at the nation's largest seller of coffee and affordable luxury. The essay assesses the corporations' reputation for being a good employer and contains extensive interviews with Wobblies trying to organize the chain. It suggests how workers are consumed by and with the brand in what the author calls “New Age welfare capitalism.”
Speaking English the Malaysian way – correct or not?
Authors: Pillai Stefanie
Published: November 2008

An examination of the give and take between local varieties and the expectations of classroom English. Like a microcosm of World Englishes, English in Malaysia is spoken in a multitude of accents characterizing different ethnic groups, socio-economic, education, language and geographical backgrounds. It is also not unusual for Malaysians to accent-switch according to context. Amidst the cacophony of local accents arise issues about whether such accents are correct or good or acceptable. This paper discusses the tension between speaking English with a Malaysian accent and the need for a pronunciation model from another variety, typically British English, in the teaching of English in Malaysia. Based on ongoing research on the pronunciation of Malaysian English, this paper suggests how this tension can be alleviated.
Lexical Simplification in Second-Language Acquisition
Authors: Blum S. , Levenston E.
Published: November 2008

The following paper is an account of empirical research in lexical acquisition, an ongoing study whose preliminary findings were reported at the Neuchâtel colloquium May 1976 (Levenston and Blum 1977). A discussion of the research methodology has also been published (Levenston and Blum 1978), as well as an attempt to link this work with studies of lexical simplification in other linguistic contexts (Blum and Levenston 1977). Before discussing in detail the current findings, it seems appropriate to summarize briefly the preceding research, of which they form an integral part.
Expressing Disagreement (Exprimer son désaccord)
Authors: Debyser Fraǹcis
Published: November 2008

In a communicative approach to language learning, the learner soon has to cope with a fundamental aspect of pragmatics: the argumentative and polemic function of language. From a pragmatic perspective, language is a tool we use not so much for describing or representing the world but for changing it, not for exchanging feelings of empathy, but for saying what we like and what we don't like, not just for expressing quiet satisfaction but for saying what is wrong, not for saying what we already know but for asking about what we want to know, not for explaining what we already have but for complaining about what we still lack and want to have: and for getting things done which would not be done if we did not ask for them and if we did not say why and how they have to be done.
The Monitor Model and Neurofunctional Theory: An Integrated View
Authors: Tollefson James W. , Jacobs Bob , Selipsky Elaine J.
Published: November 2008

The acquisition-learning distinction is the foundation for much current research in second language acquisition (SLA), yet we lack an analysis of the applicability of this distinction to the whole of the SLA process, including input, storage, retrieval, and performance. This article details the meaning of the acquisition-learning distinction in the Monitor Model and Neurofunctional Theory. It is argued that the two models provide complementary accounts of different components of the SLA process, with the Monitor Model employing the acquisition-learning distinction in an analysis of input and performance, and Neurofunctional Theory using the distinction to describe the formation of linguistic knowledge. Thus an integrated SLA model is proposed that carries the acquisition-learning distinction to all components of the SLA process and that incorporates the main elements of the Monitor Model and Neurofunctional Theory.
The Significance of Simplification
Authors: Widdowson H. G.
Published: November 2008

The notion of simplification has been a familiar one in language teaching for a long time. It underlies not only the production of “simplified readers” but also the whole process of syllabus design. Essentially, it is the pedagogic analogue of the linguist's idealization of data, from which it ultimately derives: the teacher simplifies by selecting and ordering the linguistic phenomena he is to deal with so as to ease the task of learning, and the linguist idealizes by selecting and ordering the linguistic phenomena he is to deal with to ease the task of analysis. In both cases the purpose of the operation is essentially a methodological one. And in both cases there is a danger that something crucial may be left out of account for the sake of methodological convenience. In this paper I want to suggest that something crucial IS generally left out of account and that the notion of simplification can be given a more general, and significant, definition. In the first part of the paper I shall try to work my way towards this definition and in the second part I shall cry to draw out a number of implications for language teaching pedagogy that seem to arise from it.
The acquisition of complex sentences: a cross-linguistic study
Authors: Myhill John
Published: November 2008

The paper reports the results of a test involving grammaticality judgments of English sentences given to native speakers of Spanish and Mandarin Chinese studying English as a second language. A detailed account is presented of aspects of Spanish and Chinese syntax that might explain the performance of the subjects, and an appeal is made for a more thorough search for and description of the areas of syntax in which language transfer is most likely to take place, based upon the study of acquisition data involving many different L1s and L2s. The results suggest that interference can come from sources not specified in traditional contrastive analyses and that researchers therefore must not restrict themselves to testing these analyses.
Native Speaker-Nonnative Speaker Interaction Among Academic Peers
Authors: Gaies Stephen J.
Published: November 2008

In recent years, considerable attention has been given to the way native speakers (NSs) of a language address nonnative speakers (NNSs). Indeed, research of NS-NNS conversation has become a point of convergence of a number of language research interests. Various claims have been made regarding the nature and significance of the characteristics of speech between NSs and NNSs, most important among these the notion that there exists an identifiable linguistic register which NSs consistently select for addressing less than fully proficient NNS participants.
Meta Talk in FL Classroom Discourse
Authors: Færch Claus
Published: November 2008

One way of characterizing communication in the FL classroom is in terms of what at a given time is in primary focus. Adopting a basic distinction between transactions with a focus on the FL code (meta transactions) and transactions with a focus on socio-literary or other non-linguistic content (content transactions), I argue that meta talk constitutes a largely neglected area of classroom research and address two aspects of this, each of which highlights significant aspects of meta talk: (1) The occurrence of scaffolded constructions, i.e., syntagms distributed over several turns at speech; and (2) the norms holding for talk about talk, i.e., what counts as an argument about the FL code. Following an exemplification from Danish classroom data (English and German as L2), I conclude by discussing the learning and pedagogical potential of each of these types of meta talk.
The Role of Group Work in Classroom Second Language Acquisition
Authors: Pica Teresa , Doughty Catherine
Published: November 2008

The shift in language classroom organization from teacher-fronted to student group work has received a growing amount of theoretical and empirical support (cf. Long, 1983; Long, Adams, McLean, and Castanos, 1976; Taylor, 1982). However, this practice is becoming so popular that it is in danger of turning into yet another ESL bandwagon. The following study was conducted, therefore, to evaluate the role of group work in the classroom, specifically in regard to its possible effects on classroom second language acquisition. Comparisons were made of three ESL classrooms during group vs. teacher-fronted classroom interaction on decision-making tasks.

Analysis focused on three broad categories: (1) grammaticality of input, (2) negotiation of input, and (3) individual input/production. Significant differences between the two participation patterns were indicated only in the increased amount of input and production for individual students during group interaction. Task, rather than participation pattern was shown to be a more important variable with regard to parameters (1) and (2). These results suggested that group work has a useful but somewhat restricted role in classroom second language acquisition.
Making Sense: Interlanguage's Intertalk in Exolingual Conversation
Authors: Py Bernard
Published: November 2008

This article describes processes of facilitation involved in exolingual conversation, i.e., interaction between partners who are dynamically adjusting their respective linguistic performances. The type of exolingual conversation examined in this paper is that between foreign learners and native speakers.

The foreign learner's linguistic competence, known as interlanguage, and his performance, which I refer to as intertalk, give rise to certain strategies in exolingual conversation. By studying these strategies, linguists can describe communicatively competent behavior in second language acquisition.

I conclude that such behavior is dynamic and creative, incapable of being described and defined within predetermined structures.
Learning to Communicate in the Classroom
Authors: Ellis Rod
Published: November 2008

It is now generally accepted that second language (L2) acquisition can take place as a result of learning how to communicate in the L2. It is less clear, however, whether the kind of communication that occurs in a classroom is sufficient to ensure development of full target language competence. This article examines the extent to which the opportunities for communication in an English as a Second Language (ESL) classroom result in the acquisition of one particular illocutionary act—requests. A total of 410 requests produced by two child learners over 15–21 months were examined. The results suggest that although considerable development took place over this period, both learners failed to develop either the full range of request types or a broad linguistic repertoire for performing those types that they did acquire. The learners also failed to develop the sociolinguistic competence needed to vary their choice of request to take account of different addressees. One explanation for these results is that although the classroom context fostered interpersonal and expressive needs in the two learners, it did not provide the conditions for real sociolinguistic needs.
Discourse Structure in Nonnative English Discourse
Authors: Tyler Andrea , Bro John
Published: November 2008

A frequently discussed hypothesis concerning the source of cross-linguistic communication difficulty in written discourse is conflicting organizational patterns (Kaplan, 1966, 1987). Extending the argument to oral discourse, Young (1982) argued that spoken English discourse produced by Chinese speakers evidenced a discourse-level topic-comment structure that native English speakers find difficult to follow. However, Tyler (1988) argued that the perception of incoherence might better be understood as the cumulative result of interacting miscues at the discourse level, that is, miscues in syntactic incorporation, lexical discourse markers, tense/aspect, and lexical The study reported here aims at testing these competing hypotheses. One hundred fifteen subjects rated four versions of the Chinese-produced English discourse presented in Young's study for comprehensibility. Results indicated that the effect of discourse miscues on comprehensibility was highly significant (F= 70,p<.0001). However, there was no significant effect for order of ideas (F= .47,p<.49).
The Discourse of Accommodation in Oral Proficiency Interviews
Authors: Ross Steven , Berwick Richard
Published: November 2008

Recent critical discussion of the Oral Proficiency Interview has questioned the adequacy and validity of the interview guidelines. The present study considers the role of accommodation in interview discourse and suggests that the extent of interviewer accommodation reveals an overlooked criterion for gauging the authenticity of the interview as simulated conversational interaction. The issue of misplaced accommodation as a threat to both the validity of the interview and the subsequent rating process is also raised, and supplementary criteria for training interviewers and evaluating the interview process are considered.
What Neurobiology Can Buy Language Theory
Authors: Pulvermüller Friedemann
Published: November 2008

In their paper on Universal Grammar, language acquisition, and neurobiology, Eubank and Gregg (1995) attack current attempts to specify the neurobiological correlates of language acquisition. While these authors address a large variety of topics, they make two major assertions that call for brief discussion.

First, they believe that some neurobiological accounts of language acquisition must be rejected because the authors of these accounts “give no evidence of knowing what it is that needs to be explained” (p. 53). Eubank and Gregg argue that only a language acquisition theory rooted in Government and Binding theory can be the basis of a neurobiological account of language acquisition. Government and Binding theory must be chosen because, according to these authors, it is the only welldeveloped theory of linguistic competence. To put it in a nutshell, “It is [language] acquisition theory that sets the problems for neurobiology to solve” (p. 53), and acquisition theory must conform to the Government and Binding approach. This master-and-slave view of the relationship between linguistics and biology is hard to accept, especially if one considers what Eubank and Gregg have to say about the master: Like most generative linguists, they do not hesitate to emphasize that the only well-developed linguistic theory is "not complete, of course, not yet correct in all or even most of its details, and perhaps not even in some of its fundamentals" (p. 51). It is inadequate to postulate that such a potentially insufficient construct must necessarily form the basis of biological research. This strategy may be unproductive, especially if theory-internal assumptions turn out to be wrong.
The Construction of Discourse by Nonnative Speakers
Authors: Bardovi-Harlig Kathleen , Hartford Beverly S.
Published: November 2008

This thematic issue on the construction of discourse by nonnative speakers brings together papers from a variety of perspectives. The papers illustrate how our understanding of various aspects of learner language are enriched by viewing them when situated in text. Of the variety of analyses used in this issue, the most well-known to SLA researchers investigates the organization of the text itself and the learners' ability to structure such a text. Other investigations in this issue include the study of grammatical features of interlanguage that contribute to the structure of the text and, conversely, the study of textual features that determine the use of grammatical features: neither of which may be accessible through the analysis of sentence-level production. In addition to grammatical features, the study of lexical development can be enhanced through the study of text. Whereas lexical inventories alone do not reveal the true nature of the learners' lexicon, a study of text reveals not only which lexical items are selected by learners but also how they are employed in discourse. These studies of text extend to other areas of linguistic competence as well. In the study of pragmatic competence, viewing speech acts as they are situated in speech events (e.g., the speech act of recommendation in the speech event of a letter of recommendation) not only contributes to our understanding of how certain acts are realized in context, but also how they contribute to the structure of the discourse. Finally, in the construction of text, speakers and writers must take into account the addressee.
On an extension of Wallace's pedal property of the circumcircle
Authors: Richmond H. W.
Published: November 2008

1. Mr J. P. Gabbatt has discussed in the most recent Part of the Proceedingsof this Society the Pedal locus of a simplex in hyperspace. It is, however, possible to regard the pedal property of the circumcircle somewhat differently and so to seek other extensions. Given a circle, any three points on it are vertices of an inscribed triangle, and the feet of the perpendiculars on the sides from any fourth point of the circle are collinear. Is there any curve in space on which an analogous property holds for any five points, viz. that the feet of the perpendiculars from any one upon the faces of the tetrahedron formed by the other four are coplanar?

It will be shown that curves of order n exist in Euclidean space of n dimensions on which any n + 2 points have such a property; but that the curves cannot be real if n is odd.
The wave front set of the solution of a simple initial-boundary value problem with glancing rays. II
Authors: Friedlander F. G. , Melrose R. B.
Published: November 2008

This paper is a sequel to an earlier paper in these Proceedings by one of us ((5); this will be referred to as [I]). The question considered there was that of determining the wave front set of the solution of the boundary value problem

where x∈+, y∈n, and n > 1; the precise meaning of the boundary condition at x = 0 is explained in section 1 below. The principal result of [I] can be expressed concisely by saying that singularities do not propagate along the boundary; a detailed statement is given in Theorem 1·9 of the present paper.
Parametric surfaces
Authors: Besicovitch A. S.
Published: November 2008

We shall first give some definitions concerning parametric surfaces. Denote by H a closed circle (disk) and by M a variable point on it. Let P = Ф(M) be a continuous function on H whose value P is a point in three-dimensional space. The symbols Ф(E), Ф−1(P), where E is a set of points on H and P a point in the three-dimensional space, will have their usual meaning. Ф−1(P) is a closed set. Any saturated continuum in Ф−1(P) or any point of Ф−1(P) that does not belong to such continua is called a Ф-element of H. Thus to any continuous function Ф(M) corresponds a representation of H in the form of the sum σQ of Ф-elements. The set of the pairs (P, Q), where Q runs through all Ф-elements of H and, for any Q, P = Ф(Q), is called a parametric surface, and any pair (P, Q) is called a point of the parametric surface. We shall often speak of a point Ф(M) of the parametric surface, by which we shall mean either the point (P, Q), where P = Ф(M) and Q is the Ф-element containing M, or the point P = Ф(M) of the three-dimensional space. The exact meaning will always be clear from the context. If there are exactly k points of the parametric surface whose first member is P0 we say that P0 is a point of multiplicity k. If k = 1, P0 is a simple point.
Parametric surfaces
Authors: Besicovitch A. S.
Published: November 2008

In 1914 Carathéodory defined m–dimensional measure in n–dimensional space. He considered one-dimensional measure as a generalization of length and he proved that the length of a rectifiable curve coincides with its one-dimensional measure.
The excitation functions of some (np) reactions
Authors: Bretscher E. , Wilkinson D. H.
Published: November 2008

Investigations of reactions of the type

are of interest for their own sake, and also for the fact that, if is a radioactive nucleus, as it usually is, being a stable isobar, activation of a few different A nuclei in the same fast neutron flux will yield some information about the neutron spectrum. This follows from the fact that these (np) reactions (and the similar (nα) reactions) are nearly all endothermic, showing a threshold of neutron energy below which no activation takes place. Thus knowledge of the excitation functions of a few such reactions would enable the above-mentioned crude neutron spectroscopy to be realized. The detectors (A nuclei) would have a standard shape and size, and the induced β-activity would be measured with a standard counter in fixed geometrical conditions. Though exact spectroscopy would not be possible, any change in the relative activations of the detectors would be a quite sensitive indicator of a change in the incident neutron spectrum.
On numbers with many rational approximations
Authors: Baker R. C.
Published: November 2008

Every real number α admits many rational approximations in the sense that for every natural number q,

for some integer p. Perhaps surprisingly, numbers α which have k distinct rational approximations with given denominators q1,…,qk,

for a fixed ε > 0, are quite sparse; their measure in U = [0,1) is at most C(ε)/k.
A further note on a class of integral operators
Authors: Verblunsky S.
Published: November 2008

1. Introduction. This note is a sequel to (1), the notation of which will be used without further explanation. In (2), certain deductions from the theorems proved in (1) were made in the case where K(x, t) is derived from a function K(x), a.c. in [0, 1], by the equation
Construction of rational functions on a curve
Authors: Coates J.
Published: November 2008

1. Introduction. In the study of diophantine equations in two variables, it is often necessary to consider rational functions on a curve with prescribed zeros and poles. Although it is well known that such functions can, in principle, always be effectively constructed, the detailed proof does not appear to have been given. The purpose of the present paper is to give the complete proof of such a construction. Our method, and the statement of our results, are motivated by the applications to diophantine equations which we have in mind. In particular, our results will play an important role in a subsequent paper (1), in which explicit bounds will be established for the integer points on any curve of genus 1.
On the attractive force of the gravitational field in static space times
Authors: Hagen H. Müller zum
Published: November 2008

A static metric is considered. A meaningful definition of gravitational force is given and the potential, which is the norm of the Killing vector ξa, is studied. For the case that the metric is asymptotically flat, the following is shown: The equi-potential surfaces are closed 2-dimensional surfacesSlying in the rest space V3, which is the hypersurface orthogonal to ξa. All the surfacesSenclose matter, and the gravitational force points intoStowards the enclosed matter. A test particle starting atSwill be pulled into the domain bounded bySand will never leave this domain.
Power-bounded elements and tauberian theorems in locally convex algebras
Authors: Hennings M. A.
Published: November 2008

The tauberian theorems concerning power-bounded elements of Banach algebras studied by Katznelson and Tzafriri, Allan, O'Farrell and Ransford and Allan are considered, and it is shown that (almost) exactly the same results are true for power-bounded elements in a very large class of locally convex topological algebras, the pseudo-complete algebras. The submultiplicativity of the Banach algebra norm is, for once, inessential to the proof of these theorems.
On the Differential Invariants of the Laguerre Group
Authors: Kubota Tadahiko
Published: November 2008

1. In a paper “Beiträge zur Inversionsgeometric,” which will appear in the forthcoming volume of theScience Reports of the Tôhoku Imperial University, I have treated the problem of determining the necessary and sufficient condition in order that two plane curves which are given by natural equations should be transformable into each other by inversion. In connection with that paper I propose here to treat the analogous problem for Laguerre transformations:

Having given two plane curves, by natural equations, in which the functional relations are all supposed to be analytic, it is required to determine the necessary and sufficient condition in order that the two plane curves should be transformable into each other by a Laguerre transformation.
The Problems of Random Flight and Conduction of Heat
Authors: Burnside W.
Published: November 2008

In a paper on random flight Lord Rayleigh proved the following result: A number is formed by adding together n numbers each of which is equally likely to have any value from − a to + a. Then, if f (n, s) ds is the probability that the number so formed lies between s and s + ds, and if n is sufficiently great,

This result may be stated as follows: A point moves discontinuously in a straight line. For a time τ it has a constant velocity. During the next time-interval τ it again has a constant velocity, and so on. Then if each of these velocities is equally likely to have any value from − v to + v, the probability that in the time nτ, the point moves a distance lying between s and s + ds is f (n, s) ds, with vτ written for a.
The distribution of gene frequency in a bisexual diploid population
Authors: Moran P. A. P.
Published: November 2008

In this paper we consider a model of a population in which the individuals are diploid and are of two sexes. The individuals have genotypes aa, Aa and AA and we suppose that mutation is occurring in both directions. By supposing that each step in the process is the result of a single death followed by a birth instead of supposing (as in Wright's models (3)) that all the individuals die together at the same instant, to be replaced by a new generation, the mathematical details are much simplified. In this way it is possible to deal exactly with more complicated situations than that of the population of haploid individuals used by Wright in his study of the effects of mutation in a finite population. Moreover, the present model not only involves zygotes and two sexes but is more realistic for those natural populations in which the generations are overlapping.
Diffraction by a wide slit and complementary strip. II
Authors: Millar R. F.
Published: November 2008

The notions developed in Part I in connexion with the diffraction of an E-polar-ized wave are here applied to the case of H-polarization. Induced current densities, aperture and far fields, and the transmission coefficient are again found in the form of infinite series in inverse powers of the slit-width to wavelength ratio. By means of Babinet's principle, the solution for diffraction by a strip is obtained.

A detailed comparison is made with values of the transmission coefficients for both polarizations found previously and by the present method. It appears that this theory provides accurate information when the slit-width is greater than about a wavelength.
A note on the relation between scattering phase and bound states
Authors: Polkinghorne J. C.
Published: November 2008

The form of Levinson's relation is obtained for the case where the free Hamiltonian contains discrete eigenstates. The relevance of this to the ambiguous solutions of Low equations and dispersion relations is discussed.
Why Wireless Electric Rays can bend round the Earth (Abstract)
Authors: Larmor Joseph
Published: November 2008

Mystery has remained attached to the transmission of free electric rays a long way round the protuberant curvature of the earth, which has recently developed into the greatest sudden practical evolution in signalling since the telephone. The difficulty was already emphasised by the late Lord Rayleigh, as soon as the first signs of transmission across the Atlantic had been detected by the Marconi operators. The effect has been sometimes supposed to be accounted for by a hypothesis that the rays are turned downward by an upper conducting layer in the atmosphere. But conduction, as usually understood, involves dissipation, and thus loss of energy of the rays by absorption: so that a train of radiation travelling along a layer sufficiently conducting to bend the rays could not go far. In fact, by a well-known dynamical principle, if the absorption is small of the first order, the resulting decrease of velocity of the train is small of the second order and so of no account for bending rays in a varying field.
On the current induced in a wireless telegraph receiving antenna
Authors: Moullin E. B.
Published: November 2008

The propagation of electric currents through long cables has often been treated theoretically and the solutions, first obtained by Kelvin and by Heaviside, have moulded the development of transcontinental telegraphy and telephony. These solutions presume that the source of electrical disturbance is situated at one point in the cable and this is the condition appropriate to wired communication, but in the more recent process of wireless communication we have an analogous problem which requires different terminal conditions.
Fourier series of generalized hypergeometric functions
Authors: Bajpai S. D.
Published: November 2008

1. The object of this paper is to evaluate two integrals involving Fox's H-function and employ them to establish two Fourier series for the H-function. Some Fourier series for Meijer's G-function and MacRobert's E-function are obtained as particular cases. Some results recently given by MacRobert(6, 7), Jain (4) and Kesarwani(5) are shown as particular cases.
A property of the zeros of a cross-product of Bessel functions
Authors: Willis D. M.
Published: November 2008

In this note it is shown that any positive root of the transcendental equation

is definable as a continuous increasing function of the real variable ν, provided ν is positive. Here Jν and Yν denote respectively the Bessel functions of the first and second kind of order ν, and k is a positive constant. Watson ((4)) has established the corresponding result for the simpler equations Jν(z) = 0 and Jν(z) cosα − Yν(z) sinα = 0, where α is a constant. The extension of the result to the positive roots of equation (1) is important because this equation occurs quite frequently in physical problems.
An inversion formula for the kernel Kv(x)
Authors: Fox Charles
Published: November 2008

The problem discussed is that of solving the integral equation

where g(x) is given, Kv(z) is associated with Bessel functions of purely imaginary argument and f(x) is to be determined.

I prove that, by means of fractional integration, it is possible to reduce this equation to the form of a Laplace transform which can be solved by known methods.
On the Quantum Theory of Vibration-Rotation Bands
Authors: Oppenheimer J. R.
Published: November 2008

The dynamical problem of the “diatomic molecule” is solved on the new mechanics. The terms of the rotational energy are , where ; the weights of the corresponding states are 2m; the frequencies differ a little from the classical ones. Finally the intensities are slightly different from those computed by Kemble; the main term agrees with that of Fowler, but the positive branch is only slightly stronger than the negative. The central line vanishes. The intensities are valid only for the fundamental band.
Two Dynamical Applications of Quaternion Analysis
Authors: Pocklington H. C.
Published: November 2008

1. The perturbations of a focal elliptic orbit are as easily found by Quaternions as the orbit itself.
The collision of electrons with rotating dipoles
Authors: Massey H. S. W.
Published: November 2008

The application of the quantum theory to the collision of electrons with atoms has now been worked out in some detail. For fast collisions the calculations present no difficulty, since Born's method may be applied and the probability of excitation of a given level of a simple atom can be worked out quite accurately. The corresponding problem for the case of slow collisions is much more difficult and requires a knowledge of the exact solution of the equation representing the motion of electrons in the static field of the atom considered. Using such solutions obtained by Faxén and Holtsmark's method, and allowing also for electron exchange, Massey and Mohr have been able to calculate excitation probabilities for low voltage impact in hydrogen and helium.
Degenerate surfaces in higher space
Authors: Roth L.
Published: November 2008

1. In a previous note the author has examined the systems of tangent planes to a degenerate surface in S3 consisting of n planes, regarded as the limit of a general surface of the same order. It is well known that a pair of space curves which are the limiting form of a non-degenerate curve must have a certain number of intersections; hence, if a surface in higher space degenerates into a number of surfaces, these must intersect in curves of various orders. In the present paper we consider the nature of the envelope to a surface consisting of two general surfaces of S4 having in common a single curve of general character, the degenerate surface being regarded as the limit of some surface of general type. The same conclusions hold for a similar degenerate surface in Sr (r>4).
Some comments on the relation between ionisation and ionisation current in gases at high pressures
Authors: Harper W. R.
Published: November 2008

The phenomena which limit saturation in a high pressure ionisation chamber are examined with particular reference to the rôle played by preferential recombination. The complexity of the phenomena is discussed in detail in order to bring out the scope and limitations of the simple theory of preferential recombination and the conditions which a more complete theory would have to satisfy. It is pointed out that in a number of recent papers on the subject fundamental aspects of the problem have been overlooked, and the significance of these omissions is discussed.
Some Developments in the X-ray Analysis of Single-Crystals
Authors: Aston R. L.
Published: November 2008

A method has been devised by Dr Alex Müller for determining the orientation of a single-crystal of metal by photographic measurement of the reflection of characteristic X-rays from surface layers. The incident beam passes perpendicularly through an axis of rotation around which the crystal is turned until a reflection is obtained with one of the component wave-lengths of the X-rays.
Note on the law that light-rays are the null geodesics of a gravitational field
Authors: Whittaker E. T.
Published: November 2008

In the “special” or “restricted” theory of relativity, for which the line-element ds of the “world” of space-time is given by , the geodesics of the world are straight lines, and the null geodesics (i.e. the geodesics for which ds vanishes) are the tracks of rays of light. When Einstein discovered the “general“ theory of relativity, in which the effects of gravitation are taken into account, he carried over this principle by analogy, and asserted its truth for gravitational fields; it was, in fact, the basis of his famous calculation of the deviation of light at the sun. The law was, however, not proved at the time: and indeed there is the obvious difficulty in proving it, that strictly speaking there are no “rays” of light—that is, electromagnetic disturbances which are filiform, or drawn out like a thread—except in the limit when the frequency of the light is infinitely great: in all other cases, diffraction causes the “ray” to spread out over a three-dimensional region.
A manometer for use with small Pitot tubes
Authors: Taylor G. I.
Published: November 2008

The use of Pitot tubes in exploring fields of fluid flow is well understood but the limitations of the method have not been very systematically explored.
Multiple canonical surfaces
Authors: Babbage D. W.
Published: November 2008

1. If the canonical series of an algebraic curve of genus p is compounded of an involution of sets of points on the curve then the involution must be rational and of order two, and the canonical model is a repeated rational normal curve of order p − 1 with 2p + 2 branch points. An analogous question suggests itself for algebraic surfaces. Under what conditions is the canonical model of a surface, whose geometric genus is not less than two, a multiple surface, and what in this case are the properties of the simple surface on which the multiple surface is based? In this paper we give particular examples of multiple canonical surfaces and attempt to go some way towards the solution of the general problem.
Evidence for a new type of disintegration produced by neutrons
Authors: Chadwick J. , Feather N. , Davies W. T.
Published: November 2008

The object of the present paper is to report upon a case of neutron-produced disintegration of a type which has not previously been observed. The nucleus disintegrated was that of carbon and the peculiarity of the disintegration lies in the fact that three heavy particles resulted from the transformation. Hitherto no example of such disintegration resulting in more than two heavy particles has been obtained, and with carbon, in particular, several experiments agree in showing that this more usual type of disintegration is very rare indeed. In similar circumstances, and with neutrons of less than 12 × 106electron volts energy, disintegration phenomena occur in oxygen or in nitrogen at least ten times as frequently as in carbon. Thus Harkins, Gans and Newson obtained only two examples of disintegration in 3200 pairs of photographs taken with a source of radiothorium and beryllium and an expansion chamber filled with ethylene, and concluded that in each case an atom of oxygen or some other impurity must have been involved. Likewise, Feather, in 2210 pairs of photographs with the neutrons of polonium-beryllium and an expansion chamber filled with a mixture of acetylene and helium, found only one example of a disintegration which could reasonably be ascribed to the nuclear reaction,
The application of wave-mechanics to reactions involving hydrogen and diplogen
Authors: Smith R. A.
Published: November 2008

A considerable amount of work has recently been done on the application of wave-mechanics to the theoretical study of chemical reactions. This has consisted chiefly in calculating activation energies and strengths of various bonds by consideration of electronic states in molecules. Some work has also been done on actual reaction mechanisms. It is evident from the latter that, owing to the large masses of the particles concerned, the quantum theory and the classical treatment will give different results only for reactions involving hydrogen or diplogen. Previous attempts to deal with such reactions have consisted simply of calculating the permeabilityG(W) of a barrier of height equal to the activation energy for protons of energyW.The reaction rate is then assumed to be given by
A Note on the Hall and Magneto-Resistance Effects
Authors: Shoenberg D.
Published: November 2008

Recently Kohler, on the basis of some experiments by Verleger, has questioned the validity of the usual assumption that the linear Hall effect is entirely perpendicular to the current. The available experimental data are however contradictory, so a simple magneto-resistance experiment with a bismuth crystal was made, which suggested that the usual assumption was, after all, valid. The disymmetry of the Hall effect is discussed, and some of Kohler's results are generalized.
A Rapid Mercury Still
Authors: Clark R. J.
Published: November 2008

This still is a modification of Hulett's pattern in which mercury is distilled in a current of air at greatly reduced pressure. The current of air has two uses; first it prevents bumping and so is led in beneath the surface of the boiling mercury, and secondly, it oxidizes most of the zinc, cadmium and lead which go over. The oxides float on the distillate and are easily removed by straining it. A still made according to Hulett's directions and having a boiler of half a litre capacity will distil satisfactorily about 750 grams per hour. If the rate of distillation is increased much, some of the other metals go over, and if more air is admitted to prevent this, the boiling mercury is thrown about very violently in the boiler, which breaks sooner or later.
The Statistical Theory of Dissociation and Ionization by Collision, with applications to the capture and loss of electrons by α-particles
Authors: Fowler R. H.
Published: November 2008

In two recent papers in the Philosophical Magazine the statistical theory of collisions of electrons with atoms has been considered, and applied to explain the observed features of the capture and loss of electrons by α-particles. The basis of that discussion can however be improved. Firstly, interactions with the core of any atom entered by the α-particle were explicitly ignored. Such interactions—or rather interactions with the general intra-atomic field as distinct from individual electrons—might be expected to be (and are) important, and it has been found possible to include them in this paper. Secondly, the frequency laws for the processes concerned were based on the classical Thomson-Bohr theory of ionization by collision. This theory—it is well known—does not completely reproduce experimental facts at α-particle velocities, and a less restrictive form can be given to the frequency laws which appears to be in accord with all the known facts. The application to the capture and loss of electrons by α-particles proves to be unaffected.
Improvements in the Apparatus for Measuring the Velocity of very rapid Chemical Reactions
Authors: Hartridge H. , Roughton F. J. W.
Published: November 2008

During the last six months we have succeeded in achieving two of the improvements which were foreshadowed in a former paper on this subject.
The Analysis of the β-Ray Spectrum due to the Natural L Radiation of Radium B
Authors: Black D. H.
Published: November 2008

In a previous paper the values for some lines of the β-ray spectrum of the natural L radiation of radium B have been given. The purpose of the present paper is to show that many of these lines can be accounted for by assuming that rays corresponding to L X-rays, but generated within the atom, act on various atomic levels. Before proceeding to do so, however, it will be advisable to give a fuller account of the experimental methods.
On the emission of electrons from metals covered by thin films, in intense electric fields
Authors: Stern T. E.
Published: November 2008

R. H. Fowler and L. Nordheim have presented a theory which seems to offer a satisfactory explanation of the phenomenon commonly known as the auto-electronic discharge, in which electrons are extracted from cold metallic cathodes by intense electric fields. Their theory considers the passage of electrons through a potential “hill” of the type shown in Fig. 1, where V is the potential energy of an electron at a point distant x units from the surface.
On the existence of non-combining groups of wave-functions, and on the uniqueness of the solutions of certain wave equations
Authors: Stern T. E.
Published: November 2008

Mr Ursell has given a proof in these Proceedings (vol. 24, p. 445, (1928)), that there exist non-combining groups of wave functions of an assembly of similar systems. His proof was not sufficient; but it can be amended so as to be rigorous. It will be necessary to suppose, however, that the wave function ψt is analytic for all real values of the time, for each set of space coordinates: q1, q2, q3, q4….
On some resistance properties of a certain network containing inductances and capacities and their analogies in a vibrating mechanical system
Authors: Moullin E. B.
Published: November 2008

In the network shown diagrammatically in Fig. 1, A0A3, A3A5,… are resistances of values a1, a3,… joined in series with one another, and A3B3, A5B5,…are resistances of values 1/a2, 1/a4,…: the points B0B3,… are all on a cable of negligible resistance. The members A0A3, A3A5,… will be called the series members of the network, and the members A3B3, A5B5,… will be called the shunt members of the network: the points A0B0, will be called the input terminals of the network. If a potential difference is maintained between the input terminals, currents will flow in the members of the network.