Research and debate on class size differences has focused on relations with achievement, and there is little relevant research on what mediating classroom processes might be involved. In this article we investigate connections between class size and teaching interactions. We adopt a multimethod approach, integrating qualitative information from teachers' end-ofyear accounts and data from case studies with quantitative information from time-allocation estimates and systematic observations. Our data come from a longitudinal study of two cohorts of more than 10,000 children [AQ: "each"? no overall] for 3 years after enrollment in English infant schools (aged 4-7 years). Our results show, overall, that in smaller classes there is more individualized teacher support for learning. We interpret the results in the context of teacher time allocation, research on effective teaching, and post-Vygotskian approaches to teaching. It is suggested that direct models of teacher influences on pupils need to be adapted to allow for class size as a contextual factor that influences both teachers and pupils.We start this article with a brief summary of an observer's report after a visit made to a small reception (4-5 years) class of just 15 pupils in a village school in East Sussex, England. General classroom environment.There was lightness about the activities and a good deal of humor. The teacher joked with the children (for example, comments were made at her daughter's expense concerning her propensity to hoard and store things in the loft), chatted to the observer, and discussed social things with the children. Work was not neglected; rather it was supported by a personal style of interaction. The teacher was able to maintain a running and public commentary on children's work.Classroom management. The teacher spent little time on control, and there was little need to keep children on task. There was a very noticeable contrast with the situation in another school visited at about the same time by the same observer, involving a teacher in a large class of more than 30. Interactions with the children were a continuous battle to keep their attention on task. As a consequence the teacher was severe; the children, subdued.Teaching interactions. The teacher was able to stay with one small group of children (who she felt needed her help) for the whole session, more or less. They received sustained attention and she was able to offer immediate feedback. Task allocation and preparation were deliberate, responsive, and individualized; she dealt with each of the children in turn, asked what they wanted to do from a list of activities, and then helped them to start.Teacher's knowledge of children. The teacher felt the main advantage of having a small class was that she knew children individually and that this informed her teaching. For example, on the basis of questions posed to children, she was aware of who knew and who did not know something.Hearing children read. The teacher felt very strongly that hearing children of this age read indivi...

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In this report, the mass spectral analysis of azaspiracid biotoxins is described. Specifically, the collision-induced dissociation (CID) behavior and differences between CID spectra obtained on a triple-quadrupole, a quadrupole time-of-flight, and an ion-trap mass spectrometer are addressed here. The CID spectra obtained on the triple-quadrupole mass spectrometer allowed the classification of the major product ions of the five investigated compounds (AZA 1-5) into five distinct fragment ion groups, according to the backbone cleavage positions. Although the identification of unknown azaspiracids was difficult based on CID alone, the spectra provided sufficient structural information to allow confirmation of known azaspiracids in marine samples. Furthermore, we were able to detect two new azaspiracid analogs (AZA 1b and 6) in our samples and provide a preliminary structural analysis. The proposed dissociation pathways under tandem mass spectrometry (MS/MS) conditions were confirmed by a comparison with accurate mass data from electrospray quadrupole time-of-flight MS/MS experiments. Regular sequential MS(n) analysis on an ion-trap mass spectrometer was more restricted in comparison to the triple-quadrupole mass spectrometer, because the azaspiracids underwent multiple [M + H - nH(2)O](+) (n = 1-6) losses from the precursor ion under CID. Thus, the structural information obtained from MS(n) experiments was somewhat limited. To overcome this limitation, we developed a wide-range excitation technique using a 180-u window that provided results comparable to the triple-quadrupole instrument. To demonstrate the potential of the method, we applied it to the analysis of degraded azaspiracids from mussel tissue extracts.

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There was confirmation that children in large classes are more distracted from work and more often off task. The unexpected result, based on teacher ratings, that small classes may lead to less social and more aggressive relations between children is discussed, along with implications for teachers of a tendency for more peer-related contacts in large classes.