Words by convention

Existing metasemantic projects presuppose that word- (or sentence-) types are part of the non-semantic base. We propose a new strategy: an endogenous account of word types, that is, one where word types are fixed as part of the metasemantics. On this view, it is the conventions of truthfulness and trust that ground not only the meaning of the words (meaning by convention) but also what the word type is of each particular token utterance (words by convention). The same treatment extends to identifying the populations through which the conventions prevail. We consider whether this proposal leads to new underdetermination challenges for metasemantics, and make a case that it does not

Synthetic and Mechanistic Studies in Alkaloid Chemistry

The opening section of this thesis describes the first reported preparation of potentially biologically-interesting alkoxy 1-benzyl-3(2H)-isoquinolone derivatives incorporating dissimilarly-substituted aryl rings. Treatment of alkyl 2-arylacetylarylacetates ("keto-esters") with strongly basic amines gave only 2-aryl-3-hydroxy-1,4-naphthaquinones. Reaction with hydrazine hydrate however afforded colourless labile intermediates which were readily converted into N-ainino-1-benzyl-3(2H)-isoquinolones. Similarly reaction with hydroxylamine hydrochloride in pyridine gave derivatives of N-hydroxy-1-benzyl-3(2H)-isoquinolone. Members of the series which could not be obtained from the keto-ester by these methods were available following selective reduction of the ketone function, conversion to the corresponding hydroxy-dimethylamide and re-oxidation to the keto-amide. Treatment of the latter with amines or amine acetates in hot acetic acid gave good yields of 3(2H)-isoquinolone derivatives. A somewhat unstable N-methyl 3(2H)-isoquinolone prepared in this way was also available via an alternative method, namely reaction of the keto-amide with methylamine hydrochloride in pyridine. The chemical and spectroscopic properties of the 1-benzyl derivatives appear closely to parallel those of 1-H analogues. In particular the o-quinonoid lactam tautomer appears to predominate over hypothetical stilbenoid-lactam, lactim and acyl-imine tautomers (where appropriate). An application of an earlier synthesis of alkoxy 1-H 3(2H)-isoquinolones to the preparation of the tetrahydroprotoberberine alkaloid (+/-)-norcoralydine has been completed in the present work. The second major part of the thesis constitutes an investigation into the influence of variously - oriented hydroxyl and methoxyl groupings in the Hof- mann degradation of the tetrahydrobenzylisoquinoline alkaloids, following reports that certain combinations of these substituents appeared to facilitate the elimination process. Examination of the relative rates of stilbene formation from quaternary hydroxides derived from a series of 1-N,N-dimethylaraino-1,2-diarylethanes suggested that methoxyl substituents in the 1-aryl ring did not appear to have a significant effect (at least under the conditions used). This was in sharp contrast to the effect of hydroxyl groups in positions 2 or 4 of the 1-aryl ring, decomposition of even the quaternary methiodides proceeding rapidly to stilbenes. Evidence is presented that 3-hydroxy substituents in the 1-aryl ring of 1-N,N-dimethylamino-1,2-diarylethanes and 5- or 7-hydroxy substituents in tetrahydro-benzylisoquinoline derivatives retard Hofmann elimination in the derived quaternary hydroxides by removal of hydroxide ion with formation of relatively stable phenolate zwitterions (hydroxide ion being normally responsible for initiating the decomposition of quater-nised non-phenolic amines via removal of a methylene proton to the amino moiety). In contrast, quaternised phenolic amines with hydroxyl groups in the 2 or 4 positions (aminodiarylethanes) and 6 or 8 positions (benzyl-isoquinolines) are themselves capable of facile decomposition, presumably via uncharged "quinone-methide" intermediates. The structure of an orange-red crystalline by-product formed in the course of the above work during the preparation of 1-(3,4-dimethoxy)-1-keto-2-phenylethane from veratrole and phenylacetyl chloride is shown by spectroscopic and other evidence to be 1-benzylidene-5,6-dimethoxy-2-phenyl-3-veratryl indene. The final section of the thesis deals with synthetic approaches to the pentacyclic antineoplastic alkaloid camptothecin, a constituent of the Chinese tree Camptotheca acuminata. A study of the reduction of quinoline-2,3-dicarboxylic acid derivatives as a source of potential synthetic intermediates gave mixtures of hydroxy-amides and lactones in which the heterocyclic ring was partly or wholly reduced. No 2H-pyrrolo (3,4-b) quinoline was detected and the low yields of individual products obtained made this approach less attractive than recently published syntheses

Modeling heterogeneous variance–Covariance components in two-level models

Applications of multilevel models to continuous outcomes nearly always assume constant residual variance and constant random effects variances and covar-iances. However, modeling heterogeneity of variance can prove a useful indi-cator of model misspecification and in some educational and behavioral studies, it may even be of direct substantive interest. The purpose of this article is to review, describe, and illustrate a set of recent extensions to two-level models that allow the residual and random effects variance–covariance components to be specified as functions of predictors. These predictors can then be entered with random coefficients to allow the Level-1 heteroscedastic relationships to vary across Level-2 units. We demonstrate by simulation that ignoring Level-2 variability in residual variances leads the Level-1 variance function regres-sion coefficients to be estimated with spurious precision. We discuss software options for fitting these extensions, and we illustrate them by reanalyzing the classic High School and Beyond data and two-level school effects models pre-sented by Raudenbush and Bryk.AQ

Tasks of Legal Secretaries in Oklahoma

This study is concerned with the tasks performed by legal secretaries in the State of Oklahoma. The primary objective was to determine the frequency such tasks were performed to see if the task should be incorporated in a training program. I found that the tasks described in the check lists returned were included in the material being taught to prosective legal secretaries.Occupational and Adult Educatio

A reassessment of socio - economic gradients in child cognitive development using Growth Mixture Models

Recent social and educational policy debate in the UK has been strongly influenced by studies which have found children’s cognitive developmental trajectories to be significantly affected by the socio-economic status of the households into which they were born. Most notably, using data from the 1970 British cohort study, Feinstein (2003) concluded that children from less advantaged backgrounds who scored high on cognitive tests at 22 months had been overtaken at age 5 by children from more advantaged origins, who had scored lower on the baseline test. However, questions have been raised about the methodological robustness of these studies, particularly the possibility that their key findings are, at least in part, an artefact of regression to the mean. In this paper we apply and assess the Growth Mixture Model (GMM) as an alternative approach for identifying and explaining cognitive developmental trajectories in children. We fit GMMs to simulated data and to data from the Millennium Cohort Study to assess the suitability of GMMs for studying socio-economic gradients in developmental trajectories. Our results show that GMMs are able to recover the data generating mechanism using simulated data, where the conventional approach is subject to regression to the mean. Substantively, our MCS findings provide no support for the contention that more initially able children from disadvantaged backgrounds are ‘over-taken’ in cognitive development by less initially able children from more affluent backgrounds. We do, however, find that cognitive developmental trajectories are related to socio-economic status, such that initial class-based inequalities increase over time

Quantification and Analysis of Micro-Level Activities Data from Children Aged 1-12 Years Old for Use in the Assessments of Exposure to Recycled Tire on Turf and Playgrounds.

BACKGROUND: There are growing health concerns about exposure to toxicants released from recycled tire rubber, which is commonly used in synthetic turf and playground mats. To better estimate children\u27s exposure and risk from recycled tire rubber used in synthetic turf and playground mats, there is a need to collect detailed accurate information on mouthing activity and dermal contact behaviors. The objective of this study was to quantify and analyze micro-level activity time series (MLATS) data from children aged 1-12 years old while playing (non-sport-related games) at turf-like locations and playgrounds. Another objective was to estimate the incidental ingestion rate of rubber crumb among children. METHODS: Hand and mouth contact frequency, hourly duration, and median contact duration with different objects were calculated for children playing on turf (i.e., parks, lawns, and gardens) (n = 56) and for children playing on playground structures (n = 24). Statistically significant differences between males and females as well as children\u27s age groups were evaluated. The daily incidental ingestion rate of rubber crumb was calculated. RESULTS: For children playing on turf, there were significant differences between younger (1-6 y) and older (7-12 y) children for the mouthing median duration with non-dietary objects and all objects. For children playing on playground structures, we found significant mouthing frequency differences between younger (1-6 y) and older children (7-12 y) with all objects, and for mouthing median duration with non-dietary objects. There were no significant differences between males and females playing on artificial turf-like surfaces or playground mats. Our estimated mean incidental ingestion rate was 0.08, 0.07, and 0.08 g rubber crumb/day for children DISCUSSION: our results suggest that age and contact duration should be considered in risk assessment models to evaluate mouthing activities when children are playing on artificial turf surfaces or playground mats

Climate-controlled submarine landslides on the Antarctic continental margin

Antarctica’s continental margins pose an unknown submarine landslidegenerated tsunami risk to Southern Hemisphere populations and infrastructure. Understanding the factors driving slope failure is essential to assessing future geohazards. Here, we present a multidisciplinary study of a major submarine landslide complex along the eastern Ross Sea continental slope (Antarctica) that identifies preconditioning factors and failure mechanisms. Weak layers, identified beneath three submarine landslides, consist of distinct packages of interbedded Miocene- to Pliocene-age diatom oozes and glaciomarine diamicts. The observed lithological differences, which arise from glacial to interglacial variations in biological productivity, ice proximity, and ocean circulation, caused changes in sediment deposition that inherently preconditioned slope failure. These recurrent Antarctic submarine landslides were likely triggered by seismicity associated with glacioisostatic readjustment, leading to failure within the preconditioned weak layers. Ongoing climate warming and ice retreat may increase regional glacioisostatic seismicity, triggering Antarctic submarine landslides