bluuebunny/crossref_metadata_2025 huggingface dataset:
Nitrogen availability is not affected by frequent fire in a South African savanna
Authors: Coetsee Corli , February Edmund C. , Bond William J.
Published: November 2008

There is a perception that sustained frequent fires cause nitrogen limitation over the long term (50–100 y) by volatilizing the nitrogen in soil, plant biomass and litter. Here we test this perception in a South African savanna located in the Kruger National Park. At our study site we compare the effects of 50 y of fire exclusion, season (August and February) and frequency (triennial and annual August and triennial February) of burn on nitrogen cycling and availability. We do this using three different methods to determine nitrogen mineralization; in situ incubations, laboratory incubations and ion-exchange resin bags. On each treatment we established two parallel transects 100 m apart with 10 sampling points per treatment along these transects. Daily mineralization rates for in situ incubations were determined monthly from August 2004 to June 2005 at each of the sampling points. Ion-exchange resin bags were buried (5 cm) at the same points and left in the field from August 2004 to August 2005. In February 2005 five randomly located soil samples from each of the four treatments were collected for laboratory incubations using a 7-cm-diameter soil auger. Regardless of method used our results show that there are no significant differences in daily nitrogen mineralization rates after 50 y of different burning treatments from annual burning to fire exclusion. In fact, both in situ and laboratory incubations show that nitrogen availability is higher on the annual burn than the fire exclusion (0.16 μg g−1soil d−1vs. 0.11 μg g−1soil d−1and 0.46 μg g−1soil d−1vs. 0.30 μg g−1soil d−1respectively). Perceived negative effects of fire on ecosystem functioning has curbed the use of fire as a management tool with fire often actively suppressed in savanna. The results of our study show that fire can be used more vigorously in mesic African savanna to manipulate tree:grass ratios without negatively affecting the nitrogen cycle.
Language Attrition Research: An Introduction
Authors: Weltens Bert , Cohen Andrew D.
Published: November 2008

The study of language loss—or language attrition—was recognized as a field in 1980, when the University of Pennsylvania hosted the first conference ever on the theme. Most of the contributions to this conference stressed the need for systematic empirical investigation of the phenomenon of language attrition, which everybody seems to know about, but which very few scientists had actually looked into.
On the Relevance of the Pidginization – Creolization Model for Second Language Learning
Authors: Valdman Albert
Published: November 2008

Otto Jespersen was one of the first linguists to perceive a common basis underlying all types of language acquisition and learning. Comparing pidgins, broken or approximative version of a target language, and child language, he commented:
“…. in all these seemingly different cases the same mental factor is at work, namely, imperfect mastery of a language, which in its initial stage, in the child with its first language and in a grownup with a second language learnt by imperfect method, leads to a superficial knowledge of the most indispensable words, with a total disregard for grammar”. (1921, 233–4)
Quelle recentration sur quel apprenant?
Authors: Coste Daniel
Published: November 2008

L'apprenant est aujourd'hui sinon toujours au centre des actions de formation, du moins au centre des discours didactiques dominants. Il va de soi, dans les cercles où se produit ce qu'il convient de dire et d'écrire pour être dans le vent de l'histoire pédagogique, que, par définition, tout apprentissage, quel qu'il soit, est d'abord l'affaire d'un apprenant et qu'il s'en suit que, dans un projet éducatif coherent, la figure centrale ne saurait plus être ni l'enseignant, ni la matière, ni la méthode ou le manuel, mais le “se formant”. Les stratégies, les productions, les progressions qui importent ne sont ni du maître, ni de la langue, ni du livre, mais bien du sujet qui apprend. Les motivations, les attentes et les besoins à prendre en compte, les objectifs à retenir sont avant tout ceux du sujet en formation, pilote, moteur et gouvernail d'une navigation dont il lui revient de déterminer l'itinéraire; les autres agents ayant essentiellement pour fonction d'établir les cartes marines, de baliser les routes possibles et d'aider à faire le point (tout ceci dans le mesure – faible – où ils en sont effectivement capables).
On the verbal organization of L2 tense marking in an elicited translation task by Spanish immigrants in Germany
Authors: Dittmar Norbert
Published: November 2008

This article describes the undirected learning (learning without explicit teaching) of tense markers in German by Spanish migrant workers. It will be shown that the remarkable differences the informants displayed in expressing the concept of tense are a function of the daily communicative routines which they developed in order to meet their communicative needs and demands. By examining very simplified learner varieties, I will demonstrate that a traditional grammatical analysis of tense is not capable of accounting for the wide range of expressions for temporal relations which were produced in an elicited Spanish-German translation task.
Updating the interlanguage hypothesis
Authors: Selinker Larry , Lamendella John T.
Published: November 2008

The first public presentation of the ideas leading up to the Interlanguage (IL) Hypothesis occurred a decade ago at the Second International Congress of Applied Linguistics (Selinker 1969; presented in greater detail in Selinker 1972). At that time, it was stated that, in attempting to understand the phenomenon of second-language learning, the field was at a stage where there existed an “inability to unambiguously identify the phenomena we wish to study” (Selinker 1969:35). That first presentation of the IL notion focused on the “psychologically relevant data of second-language learning,” trying to describe what it was that should be studied; the paper attempted to provide some theoretical constructs which would help identify and explain that data.
Cross Cultural Social Status Perception in Speech
Authors: Mays David V.
Published: November 2008

During the course of each day, we meet many people and form quick judgments about not only their mood and general intelligence, but about their character and social background as well. Personal appearance, facial expression, body movement, and linguistic cues are but a few of the sources of data that we interpret. It has been a matter of much debate in the last fifty years as to whether these data are cross-culturally significant, or whether they have meaning only within a given cultural milieu. This study was an attempt to determine if linguistic cues of social status have such a cross-cultural significance.
Acquiring Pronouns in a Second Language: Evidence for Hypothesis Testing
Authors: Gundel Jeanette K. , Stenson Nancy , Tarone Elaine
Published: November 2008

Gundel and Tarone (1981) studied the acquisition of pronouns by Chinese and Spanish speaking adults learning English. On the basis of this study it was proposed that when L1 and L2 differ in the relative order of object pronoun and verb, the acquisition of direct object pronouns proceeds in three stages: (1) direct transfer of the native language pattern; (2) zero anaphora, i.e. no overt form at all, in direct object position; (3) the correct L2 pattern. The present paper presents further evidence for this proposal, and hence for a hypothesis-testing view of second language acquisition, on the basis of longitudinal data from English speaking children learning French in the Toronto French Immersion Program.
Modified Input as an Aid to Comprehension
Authors: Kelch Ken
Published: November 2008

Much work in the field of second language acquisition (SLA) has focused on the linguistic adjustments made by native speakers (NSs) when speaking to non-native speakers (NNSs) of that language. Modifications of speech to NNSs are usually assumed to be an attempt to make the target language more comprehensible. The study of second language teachers' classroom discourse has contributed to a thorough description of such modifications, which in general may be termed foreigner talk (FT).
Too Many Words: Length of Utterance and Pragmatic Failure
Authors: Blum-Kulka Shoshana , Olshtain Elite
Published: November 2008

This paper investigates the theoretical and applied domains of pragmatic failure. With respect to theory, it further clarifies pragmatic failure both in native and non-native speech, and with respect to the applied domain compares request realizations of native and non-native speakers in terms of length of utterance. In discussing the results of this comparison, a number of hypotheses are put forward concerning the ways in which deviation from native norms of utterance length might be a potential cause for pragmatic failure.

The data were collected within the CCSARP (Cross-Cultural Speech Act Realization Pattern) project involving seven different languages and dialects (Blum-Kulka & Olshtain, 1984). The data were collected from both native and non-native speakers of each of the languages. The analysis of responses across several languages revealed a systematic difference in length of utterance used to realize speech acts by non-native speakers as compared to native speakers. The types of pragmatic failure that might be linked to being a non-native speaker are examined, thus continuing a line of research focusing on the pragmatic aspects of interlanguage (Blum-Kulka, 1982; Thomas, 1983; Edmondson et al., 1984).
The Expression of Temporality in Basilang Speech
Authors: Schumann John H.
Published: November 2008

This paper examines the expression of temporality in the basilang speech (the earliest stage of second language development) of five subjects. Temporality is studied from three perspectives: morphology, semantics, and pragmatics. The first analysis determined the subjects' degree of target-like use of English morphology and demonstrated that these basilang speakers generally lack verb phrase morphology and do not have a tense system. The second analysis examined the subjects' utterances in terms of sentence-level semantics, classifying utterances according to (universal) categories such as completive versus non-completive action, habitual versus continuous action, and action versus states. The analysis showed that none of the subjects studied made tense or aspectual distinctions and that temporal marking was not accomplished by the form of the verb. The third analysis examined how temporal reference was made by the adverbials (now, tomorrow, always, prepositional phrases), serialization (the fixing of a temporal reference point and allowing the sequence of utterances to reflect the actual temporal order of reported events), calendric reference (dates, days of the week, months, and numbers), and implicit reference (temporal reference inferred from a particular context or situation). This taxonomy captured the expression of time at the basilang level of interlanguage development much better than the previous two analyses.
Phonological Similarity, Markedness, and Rate of L2 Acquisition
Authors: Major Roy C.
Published: November 2008

This study investigates the interrelationship of phonological similarity between L1 and L2, transfer, and markedness as they relate to the acquisition of English /ε/ and /æ/ by native speakers of Brazilian Portuguese. Transfer and markedness adequately account for the behavior of poorer learners, but these factors do not explain the rate of acquisition of the two sounds as assessed by global foreign accent: Whereas /æ/ accuracy increased as global accent improved, /ε/ accuracy decreased. It is suggested that phonetic and phonological similarity between L1 and L2 are important factors which motivated overgeneralization or interaction of /ε/ and /æ/ within the inter-language.
On the Acquisition of Esperanto
Authors: Maxwell Dan
Published: November 2008

The claim of Esperantists that their language is easier to learn than natural languages has seldom been subjected to an empirical test, and the few tests that have been carried out are not widely known outside the Esperanto community. After an introduction to the Esperanto movement and other experiments based on the teaching of Esperanto, the two “Five-country Experiments” carried out in the 1970s are described and evaluated here. The findings of these tests support the claim of Esperantists but could be challenged mainly because of the wide range of variable factors involved in language learning. These experiments are nevertheless valuable as an attempt to measure some of these variables in a very precise way.
Constructing an Acquisition-Based Procedure for Second Language Assessment
Authors: Pienemann Manfred , Johnston Malcolm , Brindley Geoff
Published: November 2008

This article reports on a first attempt to develop and test run an observation procedure for assessing the syntactic and morphological development of adult learners of English as a second language (ESL) as evidenced in spontaneous speech production. The procedure is based on the profile analysis approach, which was first developed by Crystal, Fletcher, and Gorman (1976) for the assessment of impaired speech (English) and later adapted to the assessment of second language development (German) by Clahsen (1985). The theoretical basis of the procedure is the multidimensional model of second language acquisition (SLA) developed by Meisel, Clahsen, and Pienemann (1981) and extended to ESL acquisition by Pienemann and Johnston (1987a). According to the model, invariant developmental stages in the acquisition of certain syntactic and morphological elements in German and English can be predicted and explained in terms of hierarchically ordered speech processing constraints.

In order to assess the developmental stage of ESL learners, an observation form was drawn up, incorporating a selection of morphosyntactic features whose presence or absence in a taped sample of natural speech was monitored by assessors. The ratings made by the assessors were then compared to those assigned through a detailed linguistic analysis to test the feasibility of using a “shorthand” version of a profile analysis.

Analysis of the outcomes of the test run revealed significant correlations between the assessments and the linguistic analysis. But some variation was found in the assessors' ability to apply the assessment criteria, and the extent of agreement between the assessors' observations and the linguistic analysis was less than would be acceptable in the given theoretical framework. However, the source of these problems was identified through the first test run and suggestions were made for further refining the procedure to improve its accuracy.
An Instrumental Study of Vowel Reduction and Stress Placement in Spanish-Accented English
Authors: Flege James Emil , Bohn Ocke-Schwen
Published: November 2008

Morphophonological alternations in English words such asableversusabilityinvolve changes in both stress and vowel quality. This study examined how native speakers of Spanish and English produced four such morphologically related English word pairs. Degree of stress and vowel quality was assessed auditorily and instrumentally. Stress placement generally seemed to constitute less of a learning problem for the native Spanish speakers than vowel reduction. The results suggest that Englishlike stress placement is acquired earlier than vowel reduction and that the ability to unstress vowels is a necessary, but not sufficient, condition for vowel reduction. The magnitude of stress and vowel quality differences for the four word pairs suggests that L2 learners acquire stress placement and vowel reduction in English on a word-by-word basis.
Are Classroom and Naturalistic Acquisition the Same?
Authors: Ellis Rod
Published: November 2008

This article reports a study of the classroom acquisition of German word order rules by adult, successful language learners. Data elicited by an information-gap task performed by 39 learners of L2 Germanat two points in time are used to describe the sequence of acquisition of three obligatory word order rules. A comparison of this sequencewith that reported for naturalistic learners of German revealed no difference, despite the fact that the order in which the rules were introduced and the degree of emphasis given to the rules in the instruction differed from the naturalistic order. The classroom learners, however, did appear to be more successful than the naturalistic learnersin that they reached higher levels of acquisition in a shorter period of time. The results of this study support the claim that the classroom and naturalistic L2 acquisition of complex grammatical features such as word order follow similar routes. They also suggest that classroom learners may learn more rapidly. These findings are discussed with reference to both theories of L2 acquisition and language pedagogy.
Maturational Constraints on Language Development
Authors: Long Michael H.
Published: November 2008

This article reviews the second language research on age-related differences, as well as first language work needed to disambiguate some of the findings. Five conclusions are drawn, (a) Both the initial rate of acquisition and the ultimate level of attainment depend in part on the age at which learning begins. (b) There are sensitive periods governing language development, first or second, during which the acquisition of different linguistic abilities is successful and after which it is irregular and incomplete. (c) The age-related loss in ability is cumulative (not a catastrophic one-time event), affecting first one linguistic domain and then another, and is not limited to phonology, (d) The deterioration in some individuals begins as early as age 6—not at puberty as is often claimed. (e) Affective, input, and current cognitive explanations for the reduced ability are inadequate. The capacity for language development is maturationally constrained, and its decline probably reflects a progressive loss of neural plasticity, itself possibly associated with increasing myelination.
Speech Rate Is No Simple matter
Authors: Derwing Tracey M.
Published: November 2008

Speech rate (articulation rate and pauses) was examined for its relation to communicative success. Native English speakers (NSs) were paired with other NSs and with non-native speakers (NNSs). The subjects viewed a short film, the content of which they were to relay to their two partners independently. Communicative success was measured through comprehension questions addressed to the listeners at the completion of the task. Analyses indicated that although a slight majority of NSs slowed their speech rate for NNSs, they did not adjust articulation rate, but did significantly increase pause time. Neither speech rate nor articulation rate varied over the course of the narrations. Contrary to intuition, the subjects who successfully communicated the story to NNSs did not adjust their speech rate, while those who had difficulty communicating with NNSs increased pause time significantly. The implications of the findings are discussed, and suggestions for further research are made.
Analyzing Topical Structure in ESL Essays
Authors: Schneider Melanie , Connor Ulla
Published: November 2008

Topical structure analysis (TSA), a text-based approach to the study of topic in discourse, has been useful in identifying text-based features of coherence. It has also been used to distinguish between essays written by groups of native English speakers with varying degrees of writing proficiency (Witte, 1983a, 1983b). More recently, TSA has distinguished between higher and lower rated ESL essays, but with different results from those found with native speakers of English (Connor & Schneider, 1988). The present study replicated the previous ESL study of two groups of essays written for the TOEFL Test of Written English with three groups of essays. Findings indicate that two topical structure variables, proportions of sequential and parallel topics in the essays, differentiate the highest rated group from the two lower rated groups. We offer explanations for the results and propose that all occurrences of a particular type of topic progression do not contribute equally to the coherence of a text.
Focus-on-Form and Corrective Feedback in Communicative Language Teaching
Authors: Lightbown Patsy M. , Spada Nina
Published: November 2008

The developing oral English of approximately 100 second language learners (four intact classes) was examined in this study. The learners were native speakers of French (aged 10–12 years) who had received a 5-month intensive ESL course in either grade 5 or grade 6 in elementary schools in Quebec. A large corpus of classroom observation data was also analyzed.

Substantial between-class differences were found in the accuracy with which students used such English structures as progressive -ing and adjective–noun order in noun phrases. There was some evidence that these differences (which were not correlated with performance on listening comprehension tests) were due to differences in teachers' form-focused instruction. These findings are discussed in terms of current competing views of the role of form-focused instruction in second language learning.
Methods in Second Language Research
Authors: Grotjahn Rüdiger , Kasper Gabriele
Published: November 2008

One of the things methods in second language (SL) research and teaching have in common is that they are elusive to the question, “What is best?” The best teaching method is the one that produces the best learning outcomes, and the best research, the one that is most capable of fulfilling a given research purpose. In both cases, the reply to the optimal method question thus depends on the specific teaching/research goal and a range of contextual factors.
Second Language Speech Production Research
Authors: Crookes Graham
Published: November 2008

Recent SLA theory development, supported by related developments in cognitive psychology, has made the study of SL speech production, hitherto neglected, a promising area of work. Recent developments in L1 production studies have provided a gradually strengthening foundation for investigations of L2 production with both use and acquisitional concerns. This article briefly sketches the current first language position as a necessary preliminary to a critical discussion of recent SL production research with particular regard to methodology.
The Research Programme Subjective Theories
Authors: Grotjahn Rudiger
Published: November 2008

Subjective theories are very complex cognitive structures: they are highly individual, relatively stable, and relatively enduring. Examples are learners' and teachers' general beliefs about language, and about learning and teaching. In psychology and educational science it has been demonstrated that subjective theories are an important tool for the explanation and prediction of human action and thinking, and a special methodology for their analysis has been developed. It is characteristic of this methodology that it is based on both hermeneutics and empiricism, which are integrated into a coherent framework. In the present article, it is argued that the concept of subjective theory and the corresponding methodology have a considerable potential for second language research. The methodology is discussed at some length, and its application to second language research is shown.
Perception of English Voicing by Native and Nonnative Adults
Authors: Bond Z. S. , Fokes Joann
Published: November 2008

Recordings of naturally produced stop-vowel English words with a wide range of voice onset time values were used to investigate nonnative perception of voicing categories. L2 learners of English from nine language groups and native American English speakers served as subjects. The responses of the language learners suggested that they were using a hybrid perceptual system, one in which the English voicing categories were not yet fully established.
Theory Construction in SLA
Authors: Beretta Alan
Published: November 2008

There are indications that a determined effort toward theory construction is currently being mounted in SLA (Gregg, 1989, 1990; Long, 1990; Spolsky, 1989). This raises a number of epistemological issues, one of which is the question of multiple theories and lack of convergence (and the related question of distinguishing science from nonscience–and from nonsense). In a field where there are many different therorise, is the relationship between them one of complementarity or of opposition? Are there criteria for appraisal and choice? Issues relating to theory construction have received considerable attention in the literature (e.g., Lightbown, 1984; McLaughlin, 1987). This article aims to build on such initiative asking: (a) Are there multiple theories of SLA? (b) Is it a problem? and (c) what criteria have SLA researchers used to appraise and choose between theories, and how compelling are they? Following this, consideration is given to top-down and bottom-up approaches to SLA theory construction. I conclude by advancing the modest claim that rationality in SLA therory construction is possible, in spite of insistent problems.
Reexamining the Critical Period Hypothesis
Authors: Ioup Georgette , Boustagui Elizabeth , El Tigi Manal , Moselle Martha
Published: November 2008

This study concerns the ability of adults to achieve nativelike competence in second language when the acquisition context lacks formal instruction and, therefore, more closely resembles the environment for first language acquisition. The study presents the results of extensive testing of an adult who has apparently acquired native proficiency in Egyptian Arabic (EA) in an untutored setting. The goal is to determine to what extent her linguistic competence matches that of native speakers. Measures employed to assess her level of achievement are a speech production task, a grammaticality judgment task, a translation task, an anaphoric interpretation task, and an accent recognition task. Results are compared to those of native speakers as well as to those of a proficient learner of EA with extensive formal instruction. The results lead the authors to reexamine the critical period hypothesis while addressing the role of talent in adult language learning. The study concludes with an evaluation of our subject's language learning history to discover what factors differentiate her from less successful naturalistic adult acquirers.
Discourse Motivations for Some Cognitive Acquisition Principles
Authors: Andersen Roger W. , Shirai Yasuhiro
Published: November 2008

This paper offers an alternative interpretation for what has been called the defective tense hypothesis, the primacy of aspect hypothesis, or simply the aspect hypothesis in the literature on first and second language acquisition of tense and aspect. The aspect hypothesis states that first and second language learners will initially be influenced by the inherent semantic aspect of verbs or predicates in the acquisition of tense and aspect markers associated with or affixed to these verbs. Our account focuses on the observation that adult native speakers also appear to adhere to this primacy of inherent semantic aspect in the relative quantitative distribution of tense-aspect markers in their speech. We argue that a small set of cognitive operating principles and the notion of prototypicality account for this behavior in learners. Moreover, we argue that these principles are a consequence of how learners and native speakers alike organize information and their perspectives on it in ongoing discourse.
“Et in Amygdala Ego”?
Authors: Eubank Lynn , Gregg Kevin R.
Published: November 2008

John Schumann and colleagues (Jacobs, 1988; Jacobs & Schumann, 1992; Pulvermüller & Schumann, 1994; Schumann, 1990a, 1990b) have argued for a neurobiological perspective on language acquisition, one that denies a role for a specifically linguistic mental module of the sort proposed by, for example, Chomsky (e.g., 1986). In this paper, we challenge this perspective by offering evidence that such a mental module must be involved in the acquisition of grammatical competence.
Sequencing in SLA
Authors: Ellis Nick C.
Published: November 2008

This paper provides an overview of sequencing in SLA. It contends that much of language acquisition is in fact sequence learning (for vocabulary, the phonological units of language and their phonotactic sequences: for discourse, the lexical units of language and their sequences in clauses and collocations). It argues that the resultant long-term knowledge base of language sequences serves as the database for the acquisition of language grammar. It next demonstrates that SLA of lexis, idiom, collocation, and grammar are all determined by individual differences in learners' ability to remember simple verbal strings in order. It outlines how interactions between short-term and long-term phonological memory systems allow chunking and the tuning of language systems better to represent structural information for particular languages. It proposes mechanisms for the analysis of sequence information that result in knowledge of underlying grammar. Finally, it considers the relations between this empiricist approach and that of generative grammar.
Pragmatic Transferability
Authors: Takahashi Satomi
Published: November 2008

This study examines the transferability of five Japanese indirect request strategies to corresponding English request contexts. Pragmatic transferability was operationally defined as transferability rate. This rate was established through the summation of the perceived contextual appropriateness of a Japanese request and the perceived similarity in contextual appropriateness between a Japanese request and its English equivalent. The Japanese request strategies were found to be differentially transferable. The learners' transferability perception was influenced by their L2 proficiency; however, there was no definite tendency for a positive correlation nor for a negative correlation between L1 transfer and proficiency. Furthermore, the transferability of each L1 request strategy seemed to be determined by the interaction between the politeness and conventionality encoded in each strategy and the degree of mitigation required in each imposition context.
Comprehension processes in L2 reading: Language competence, textual coherence, and inferences
Authors: Horiba Yukie
Published: November 2008

The study reported in this paper examined four groups of readers (L2-Intermediate, L2-Advanced, L1-Japanese, and L1-English) when they processed and recalled two passages that varied in degree of causal coherence (Trabasso & van den Broek, 1985). Concurrent verbal reports and recall data were collected. It was found that L1 readers used much of their attention for higher level processes such as the generation of inferences and general knowledge associations. They processed the high- and low-coherence texts differently, generating more elaborations for low-coherence texts than for high-coherence texts. Furthermore, L1 readers generated backward inferences according to the text's causal structure and recalled events with many causal connections more frequently than events with few connections. These findings confirm L1 research findings (Fletcher & Bloom, 1988; Goldman & Varnhargen, 1986; Graesser & Clark, 1985; Singer, 1995; Trabasso & van den Broek, 1985; van den Broek, 1994). On the other hand, L2 readers paid more attention to lower level processes and did not process differently between the high- and low-coherence texts. L2-Advanced readers generated both backward and forward inferences during reading, whereas L2-lntermediate readers did not. Although L2-Advanced readers' generation of backward inferences did not correspond to the text's causal structure, their second recall indicated they were sensitive to it. A closer look at the data suggests that there were some delays in lower level processes such as understanding words and sentences, as well as resolution of anaphoric relations by these readers.
Black-hole magnetostatics
Authors: King A. R.
Published: November 2008

The general multipole solutions obeying the appropriate boundary conditions are presented for stationary non-axisymmetric electromagnetic fields in the Kerr background geometry.
The hydrodynamics of non-Newtonian fluids. II
Authors: Rivlin R. S.
Published: November 2008

In this paper, the general hydrodynamic theory of visco-inelastic, incompressible, non-Newtonian fluids, developed in a previous paper (l), is applied to the problem of the flow of such a fluid through a tube of circular cross-section. It is found that the absolute values of the normal stress components are no longer uniform over a cross-section of the tube normal to its axis, as in the case of Newtonian fluids obeying the laws of classical hydrodynamics.

However, the pressure difference, between points at equal radii on two planes normal to the axis, is independent of the position of these points on the planes.
Optimal intersections of plane lattice points with vertical and horizontal straight lines
Authors: Cheng Sui-Sun , Huang Yu-Tai
Published: November 2008

A point in the plane is said to be a lattice point if it has integral coordinates. Given a set C of lattice points and two non-negative integers m and n, we are concerned with determining a set of m vertical and a set of n horizontal straight lines so that the number of intersections of these sets is maximal. In general, this problem is rather difficult, since we have to make simultaneous decisions about the positions of the vertical and horizontal straight lines. Our purpose here is to study a set of lattice points of the form (i, j) such that i, j, i + j and i − j are bounded by fixed integers. We shall show that, in this case, sequential decisions can be made about the two families of straight lines.
On the minimal dimensions of irreducible representations of symmetric groups
Authors: James G. D.
Published: November 2008

For each integer m, Rasala [6] has shown how to list all the ordinary irreducible representations of the symmetric group n which have degree less than nm, provided that n is large enough, and in this note we shall prove similar results for the irreducible representations of n over an arbitrary field K. Our estimates are very crude, so although we recover Rasala's results, we get nowhere near his precise information on how large n has to be.
Some distribution and moment formulae for the Markov renewal process
Authors: Kshirsagar A. M. , Wysocki R.
Published: November 2008

1.Introduction. A Markov Renewal Process (MRP) withm(<∞) states is one which records at each timet, the number of times a system visits each of themstates up to timet, if the system moves from state to state according to a Markov chain with transition probability matrixP0= [pij]and if the time required for each successive move is a random variable whose distribution function (d.f.) depends on the two states between which the move is made. Thus, if the system moves from stateito statej, the holding time in the stateihasFij(x)as its d.f. (i, j= 1,2, …,m).
Another characteristic property of the Poisson distribution
Authors: Shanbhag D. N.
Published: November 2008

1. Introduction: In (4) Moran considers two independent random variables X and Y taking non-negative integral values to give a characterization of the Poisson distribution. He establishes that the conditional distribution of X, given the total X + Y, is binomial for all given values of X + Y and there exists at least one i so that P(x = i) > 0, P( Y = i) > 0 if and only if X and Y have Poisson distributions. A slightly improved version of this result is given by Chatterji (1). For a comprehensive bibliography on the Poisson distribution the reader is referred to (3).
On the Proof of a Lemma Enunciated by Severi
Authors: Baker H. F.
Published: November 2008

1. There is a lemma given by Severi which is of importance because it is used by him in his proof that the number of finite Picard integrals belonging to an algebraic surface is equal to the irregularity of the surface; it is also used by Castelnuovo † in his proof of the same result. The lemma is: If upon an algebraic curve there is an irreducible algebraic series, ∞1, of sets of s points, of index r; and if the sets of sr points which consist of all the r sets which contain a given point (this point taken r times) move in a linear series as this point varies, then any one of the r sets of s points separately moves in a linear series. The proof given by Severi was held satisfactory by Castelnuovot, but I find difficulty in stating it with precision; and Castelnuovo gives an entirely different proof, founded on an enumerative formula due to Schubert (loc. cit. p. 341); this is also the course adopted by Enriques-Chisini.
Determination of the Energy Distribution of Recoil Atoms During β Decay and the Existence of the Neutrino
Authors: Leipunski A. I.
Published: November 2008

It is a well-known fact that the non-conservation of energy during β decay may be explained by assuming the existence of light neutral particles, neutrinos, which are ejected from the nucleus at every act of β emission and which enable all the conservation laws to be fulfilled. A study of the energy distribution of recoil atoms during β decay might furnish some data for testing this hypothesis. However, in order to determine the energy distribution of recoil atoms consider-able experimental difficulties have to be overcome. The energy of recoil atoms of ordinary radioactive substances is of the order of magnitude of 1 volt, i.e. of the same order of magnitude as the adsorption energy of atoms on a surface. Thus, on escaping from the'surface on which they are adsorbed, they will lose an amount of energy of the same order of magnitude as that which they possess, and their velocity distribution will therefore be completely distorted. This difficulty may be met by employing an artificial, light radioactive substance, whose recoil atoms may have energies some ten times greater than 1 volt. For this reason active carbon C, obtained by bombarding boron with deuterons according to the reaction 10B+2H→11C+n, was employed as a radioactive substance. Moreover, the fact that the emission of positrons from 11C is not accompanied by the emission of γ-rays has the advantage of simplifying the interpretation of the results.
The solution of an infinite set of differential-difference equations occurring in polymerization and queueing problems
Authors: Wragg A.
Published: November 2008

The time-dependent solutions of an infinite set of differential-difference equations arising from queueing theory and models of ‘living’ polymer are expressed in terms of modified Bessel functions. Explicit solutions are available for constant values of a parameter describing the arrival rate or monomer concentration; for time-dependent parameter a formal solution is obtained in terms of a function which satisfies a Volterra type integral equation of the second kind. These results are used as the basis of a numerical method of solving the infinite set of differential equations when the time-dependent parameter itself satisfies a differential equation.
Scattering of plane waves by locally homogeneous dielectric noise
Authors: Silverman Richard A.
Published: November 2008

The scattering of acoustic and electromagnetic radiation by random refractive index fluctuations of the scattering medium (e.g. the troposphere, the ocean) is a problem of considerable contemporary interest. For brevity, we shall refer to these refractive index fluctuations as dielectric noise. The purpose of this paper is to compare two approaches to the problem of the scattering of incident plane waves by a confined region of dielectric noise. In the first approach, which is the conventional one, the scattering dielectric noise is represented as a ‘section’ of a homogeneous (i.e. spatially stationary) random process. In the second approach, which is based on a recent generalization of the notion of stationarity (1), the scattering dielectric noise is represented as a locally homogeneous random process. The advantage of representing the dielectric noise as a locally homogeneous process, rather than as a homogeneous process, is that one can thereby take into account in a natural way the spatial variation of the average noise power, without departing from the physically reasonable requirement that the process be approximately homogeneous in suitably restricted domains.
On the Vector Algebra of Eight Associated Points of Three Quadric Surfaces
Authors: Turnbull H. W.
Published: November 2008

Let the eight points in space common to three arbitrary quadric surfaces be called eight associated points. These points possess the property that any one of them is uniquely determined if the other seven are given. It is interesting to give the analytical expressions for eight associated points in terms of symbols entirely free from coordinate systems. Thus we take the first eight digits 1, 2,…8 to denote the points; a group of two digits to denote the line joining these two; a group of three to denote a plane, and so on. Also a conjunction of two groups denotes the point, line or plane common to the two groups, thus (34, 678) is the point common to the line 34 and the plane 678.
Note on the Chemical Constant of Chlorine
Authors: Cox R. R. S.
Published: November 2008

Since the publication of a previous paper on chemical constants, some further experimental data upon the dissociation of chlorine by Wohl have appeared, from which a new and rather more satisfactory value of the chemical constant of diatomic chlorine can be calculated. Wohl concludes that Q0, the heat of dissociation at absolute zero, is – 57,000 calories. This is in good agreement with Henglein's value – 54,000 but differs from that of Trautz and Stackel, namely – 71,000, which is the value adopted in the previous paper. Q0 is necessarily an adjustable constant, and since Wold's value gives results which are a good deal more concordant with each other and with the theory, we now take Q0 = − 57,000. Wohl also uses hv0/k = 902 instead of 1093, but as the difference made by this change is very small compared with other disagreements, we retain the value 1093. The following table gives the new values of Γ (Cl2), calculated in the same way as before. The initials at the heads of the columns refer to the results of Henglein, Trautz and Wohl respectively.
Dissociative Equilibrium in an External Field of Force
Authors: Milne E. A.
Published: November 2008

(1) The conditions of dissociative equilibrium in an external gravitational field have been given by Willard Gibbs, as follows: If the state of a system is such that it is in (mechanical and thermodynamic) equilibrium when the constituents are taken to be independent, and if a condition of dissociative equilibrium is satisfied at one point, then the same condition is satisfied at all points, and the state is one of equilibrium if the constituents are actually capable of dissociating.

(2) In particular, the constituents of a column of dissociating gas under gravity settle out according to Dalton's law; if the condition of dissociative equilibrium is satisfied at one height it is satisfied at all heights.

(3) The conditions of equilibrium are generalised so as to take account of external electric fields and of the possibility of the products of dissociation being charged. Result (1) is shown to be unaffected.

(4) The theory is applied to the equilibrium of an ionized gas such as a stellar atmosphere under gravity. Whatever the charge on the star, the tendency of the light electrons to diffuse away from the heavy ions is almost entirely prevented by the electrostatic forces between them, and the result is the production of a field in the interior capable of supporting half the weight of the positiveions (Pannekoek, Rosseland). For the purposes of this statement the “interior” may be taken to commence at a pressure of 10−24 atmos. It is only above the level corresponding to 10−34 atmos. that electrons and ions separate out according to Dalton's law.

(5) The theory is applied to the equilibrium of an ionized gas under an external electric field. An external applied field of the order of 40,000 volt cm.−1 cannot give rise to potential differences exceeding about 1 volt under the conditions of a typical stellar atmosphere.
An infinite summation formula associated with Appell's function F2
Authors: Srivastava H. M.
Published: November 2008

1. Recently in these proceedings we proved that, if ℜ(α) > 1 and ℜ(α) > − 1, then ((10), p. 1088)

where F2 denotes the Appell function (see, e.g., (8), p. 211),

with, as usual,

and for covergence of the double series,

and x⇌y indicates the presence of a second term that originates from the first by interchanging x and y.
Stagnation flow against a rotating magnetized disc
Authors: D'Sa E. R.
Published: November 2008

The problem stated in the title is studied for small values of the diffusivity ratio ε and the magnetic force coefficient N with the aim of finding the effect of rotation and the disc conductivity on the magnetic and velocity fields, currents, shear stresses, etc.
An interpretation of the Kerr metric in general relativity
Authors: Boyer R. H. , Price T. G.
Published: November 2008

The preceding paper ((1)) dealt with some general properties of the gravitational field of a rotating fluid mass. An interesting example of a vacuum solution that might be the exterior field of some rotating body was recently found by Kerr ((4)). It was natural to apply the preceding theory to the Kerr solution. This paper deals with other aspects of that solution, particularly the behaviour of its bounded geodesics (planetary orbits). It would seem desirable to know what sort of rotating body could be a source of the Kerr field. It will appear that one of the parameters in Kerr's solution can plausibly be related to the angular momentum per unit mass of a uniformly rotating sphere, the other parameter being a measure of the mass of the sphere.
A Mathematical Theory of Natural Selection. Part VIII. Metastable Populations
Authors: Haldane J. B. S.
Published: November 2008

Almost every species is, to a first approximation, in genetic equilibrium; that is to say no very drastic changes are occurring rapidly in its composition. It is a necessary condition for equilibrium that all new genes which arise at all frequently by mutation should be disadvantageous, otherwise they will spread through the population. Now each of two or more genes may be disadvantageous, but all together may be advantageous. An example of such balance has been given by Gonsalez(1). He found that, in purple-eyed Drosophila melanogaster, arc wing or axillary speck (each due to a recessive gene) shortened life, but the two together lengthened it.
A Generalization of Feuerbach's Theorem
Authors: Gabbatt J. P.
Published: November 2008

It is well known that in non-euclidean geometry a plane triangle has four circumcircles, and that each of these circles touches each of four other circles. The latter theorem, which is an extension of that of Feuerbach, is essentially due to Hart.
Triple Binary Forms; the complete system for a single (1, 1, 1) form with its geometrical interpretation
Authors: Saddler W.
Published: November 2008

In the Transactions of the American Math. Society, vol. I, 1900, and vol. IV, 1904, Mr E. Kasner treats exhaustively the (2, 2) double binary form and discusses the theory connected with double binary forms and multiple binary forms in general terms. He shows the relations between the systems of multiple binary forms with digredient variables and the forms with cogredient variables. Hitherto nothing seems to have been written on systems of triple binary forms (with regard to higher forms see a paper on the (1, 1, 1, 1) form by C. Segre); so here I propose to discuss the complete system of a (1, 1, 1) binary form which consists of six forms connected by one syzygy. When two of the variables are the same we naturally get the (2, 1) form and when the three are the same We get the (3) or cubic binary form.