To send content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about sending content to .
To send content items to your Kindle, first ensure email@example.com
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about sending to your Kindle.
Note you can select to send to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Identifying the mechanisms linking early experiences, genetic risk factors, and their interaction with later health consequences is central to the development of preventive interventions and identifying potential boundary conditions for their efficacy. In the current investigation of 412 African American adolescents followed across a 20-year period, we examined change in body mass index (BMI) across adolescence as one possible mechanism linking childhood adversity and adult health. We found associations of childhood adversity with objective indicators of young adult health, including a cardiometabolic risk index, a methylomic aging index, and a count of chronic health conditions. Childhood adversities were associated with objective indicators indirectly through their association with gains in BMI across adolescence and early adulthood. We also found evidence of an association of genetic risk with weight gain across adolescence and young adult health, as well as genetic moderation of childhood adversity's effect on gains in BMI, resulting in moderated mediation. These patterns indicated that genetic risk moderated the indirect pathways from childhood adversity to young adult health outcomes and childhood adversity moderated the indirect pathways from genetic risk to young adult health outcomes through effects on weight gain during adolescence and early adulthood.
Microelectromechanical systems (MEMS) are increasingly at our fingertips. To understand and thereby improve their performance, especially given their ever-decreasing sizes, it is crucial to measure their functionality in situ. Atomic force microscopy (AFM) is well suited for such studies, allowing nanoscale lateral and vertical resolution of static displacements, as well as mapping of the dynamic response of these physically actuating microsystems. In this work, the vibration of a tuning fork based viscosity sensor is mapped and compared to model experiments in air, liquid, and a curing collagen gel. The switching response of a MEMS switch with nanosecond time-scale activation is also monitored – including mapping resonances of the driving microcantilever and the displacement of an overhanging contact structure in response to periodic pulsing. Such nanoscale in situ AFM investigations of MEMS can be crucial for enhancing modeling, design, and the ultimate performance of these increasingly important and sophisticated devices.
The formal commissioning of the IRWG occurred at the 1991 Buenos Aires General Assembly, following a Joint Commission meeting at the IAU GA in Baltimore in 1988 that identified the problems with ground-based infrared photometry. The meeting justification, papers, and conclusions, can be found in Milone (1989). In summary, the challenges involved how to explain the failure to achieve the milli-magnitude precision expected of infrared photometry and an apparent 3% limit on system transformability. The proposed solution was to redefine the broadband Johnson system, the passbands of which had proven so unsatisfactory that over time effectively different systems proliferated, although bearing the same “JHKLMNQ” designations; the new system needed to be better positioned and centered in the spectral windows of the Earth's atmosphere, and the variable water vapour content of the atmosphere needed to be measured in real time to better correct for atmospheric extinction.
Recombination between F42lac and λplac5 is typically 20- to 50-fold more efficient than recombination between chromosomal lac and λplac5. This enhancement of recombination is recBCD-dependent and requires the expression of genes from the tra regulon of the F factor. Also required is oriT, the origin of F factor conjugational transfer, which must be located in-cis to the cellular copy of lac. In this study we show that enhanced recombination is not supported by an oriT point mutant that reduces oriT function in conjugation. We also present evidence that the activation of oriT for recombination enhancement involves the same strand-specific nick that is required for conjugal DNA transfer. Although it is thought that the role of oriT in recombination enhancement is related to the facilitated entry of RecBCD enzyme into the DNA duplex, we were unable to detect any double-strand breakage at oriT.
In chapter 1 we outlined some of the basic corpus techniques, including the creation of frequency lists for single words, the generation of collocational statistics, information on the occurrence of clusters, and the use of concordances for the investigation of items in context. One of the most obvious things we can do with the first of these, frequency information, is to ascertain how many words native speakers use, how frequently they have recourse to the individual words they use and how they combine them, and to explore to what extent words have become part of regularly occurring chunks or clusters for the native user. In this chapter we look at some of this evidence and consider how relevant or useful it is for understanding the vocabulary needs of second language learners and for establishing benchmarks by which learners' vocabulary levels can be assessed and evaluated and by which we may come to some general agreement as to what constitutes the various levels of proficiency in vocabulary knowledge.
It is important to state from the outset, however, that just because native speakers can understand a particular number of words and use them in particular ways, it is not necessarily so that L2 learners must be judged solely against native-user standards. In other words, we must not view second language learners as ‘failed monolinguals’, as Cook (1998) aptly puts it.
This book set out to explore links between corpus linguistics and language teaching. We have argued that there are many connections to be made, but that forging the links has to be a two-way process. For corpus linguistics to adequately inform language teaching, teachers need to inform corpus linguists. In order for this to be realised, some form of corpus linguistics should ideally become a core part of teacher education and development. On one level, we have tried to show the application and importance of corpus-based findings for language teaching, but on another level, we have sought to raise teachers' interest in using language corpora themselves to pursue their own inquiries and enhance their professional development. Corpus linguists are interested in finding exciting insights about language, but these are not always relevant or exciting for language teachers. Here we have looked at a wide range of research findings in English corpus linguistics that have brought us forward in our understanding of pedagogy and materials design, but this is by no means an exhaustive treatment. While much has been achieved, it is only the start of the synergy between corpus linguistics and language teaching.
There are many more research questions to be explored which will lead us to insights and applications for language teaching in the future. These research questions need to be driven by teachers, and indeed a more critical response to the findings of corpus linguistics needs to come from teachers.
In Chapter 2, although we focused primarily on single words, we also made occasional mention of the status of chunks as an element of the lexical competence of Successful Users of English (SUEs) (see chapter 1), noting that some chunks (e.g. a couple of, at the moment, all the time) were every bit as frequent as ordinary, everyday single words such as possible, alone, fun, expensive. Our argument was that, ideally, corpus information on chunks should be dovetailed into the information on single words in order to get a full picture of what needs to be learnt at the various levels of vocabulary attainment.
The title of this chapter is ambiguous. Corpus analysis, as we have seen, is relatively easy and straightforward when the computer is asked to search for and list single words. However, when we expand our search criteria to look for recurrences of more than one word (i.e. pairs and trios of words and even larger groupings), things become more complicated, and there are lessons to be learned about how we describe the vocabulary of a language, as well as implications for what teachers teach in their vocabulary lessons and how learners approach the task of acquiring vocabulary and developing fluency. But first we shall consider how the traditional view of vocabulary, where vocabulary means all the single words of a language, has changed over the years, especially in light of corpus analysis.
In chapters 2 and 3 we took a systematic look at the core words and chunks in English and this showed us that many of the most frequent items in the spoken corpora had pragmatic functions in the organisation and management of conversation and in the speaker-listener relationship, particularly in terms of maintaining good relations. These high frequency words and chunks illustrate the pervasiveness of interactive meaning-making in everyday conversation. They also point to the degree to which speakers constantly engage with each other on the interactive plane. Many of the items that we identified in chapters 2 and 3 fell into the broad functional categories shown in table 1 (overleaf).
In order to understand these features better, we introduce the notion of relational versus transactional language. When we talk about relational language, we are referring to language which serves to create and maintain good relations between the speaker and hearer, as opposed to transactional language, which refers to the exchange of information between speakers (i.e. the propositional content of the conversation). However, we are not saying that all language can be strictly divided into either relational or transactional types. Relational episodes can be found in what are ostensibly transactional interactions and vice versa. Iacobucci (1990), who looks at customer calls to a phone company concerning billing queries, provides interesting insights into the importance of ‘apparently relational-oriented talk’ (p. 97) integrated with the transactional tasks.
In recent years, conferences on applied linguistics and teacher development, as well as published material such as books, articles and newsletters, frequently refer to developments and findings in the field of corpus linguistics. An increasing number of materials and resources for use in language teaching and learning now boast that they are ‘corpus-based’ or ‘corpus-informed’. Indeed, in the pioneering area of learners' dictionaries, one could hardly imagine any major publisher nowadays putting out a dictionary that was not based on a corpus, such was the revolution sparked off by Sinclair's COBUILD dictionary project in the 1980s. Similarly, corpus information, in recent years, seems to be becoming de rigueur as the basis of the compilation of major reference grammars, and, more and more, as a major feature of coursebooks, though here the picture is more patchy at the time of writing.
However, widespread use of ‘corpus linguistics’ does not mean that the term or its findings are necessarily fully or widely understood in the context of language pedagogy. In addition, many important developments in the field of corpus linguistics are not always communicated or usefully mediated in terms of their implications for language teaching. This is possibly because corpus linguists are very often not language teachers and spend a lot of time talking with one another rather than with teachers. This book aims to address the frequent mismatch between corpus linguistics research and what goes into materials and resources, and what goes on in the language classroom.
Here we look at the basics of corpus linguistics, from what a corpus is to how to build one. We outline the basic functions of corpus software, such as generating word frequency lists and concordance lines of words and clusters (or chunks). We also try to give an idea of the wide range of applications of a corpus to fields as diverse as forensic linguistics and language teaching. Creating a corpus also brings up a number of issues, for example, whose language it is representing. This is particularly the case in relation to corpora of English in the context of native versus non-native speaker users of the language.
What is a corpus and how can we use it?
A corpus is a collection of texts, written or spoken, which is stored on a computer. In the past the term was more associated with a body of work, for example all of the writings of one author. However, since the advent of computers large amounts of texts can be stored and analysed using analytical software. Another feature of a corpus, as Biber, Conrad and Reppen (1998) point out, is that it is a principled collection of texts available for qualitative and quantitative analysis. This definition is useful because it captures a number of important issues: