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This article explores the strengths and weaknesses of Lave and Wenger's concept of 'legitimate peripheral participation' as a means of understanding workplace learning. It draws on recent ESRC-funded research by the authors in contemporary workplace settings in the UK (manufacturing industry and secondary schools) to establish the extent to which Lave and Wenger's theories can adequately illuminate the nature and process of learning at work. The new research presented here, which was located in complex institutional settings, highlights the diverse nature of patterns and forms of participation. Case study evidence is used to identify individual and contextual factors which underpin and illuminate the ways in which employees learn. The paper argues that whilst Lave and Wenger's work continues to provide an important source of theoretical insight and inspiration for research in to learning at work, it has significant limitations. These limitations relate to the application of their perspective to contemporary workplaces in advanced industrial societies and to the institutional environments in which people work. These complex settings play a crucial role in the configuration of opportunities and barriers to learning that employees encounter.

A search for diphoton resonances in the mass range between 10 and 70 GeV with the ATLAS experiment at the Large Hadron Collider (LHC) is presented. The analysis is based on pp collision data corresponding to an integrated luminosity of 138 fb −1 at a centre-of-mass energy of 13 TeV recorded from 2015 to 2018. Previous searches for diphoton resonances at the LHC have explored masses down to 65 GeV, finding no evidence of new particles. This search exploits the particular kinematics of events with pairs of closely spaced photons reconstructed in the detector, allowing examination of invariant masses down to 10 GeV. The presented strategy covers a region previously unexplored at hadron colliders because of the experimental challenges of recording low-energy photons and estimating the backgrounds. No significant excess is observed and the reported limits provide the strongest bound on promptly decaying axion-like particles coupling to gluons and photons for masses between 10 and 70 GeV.

A search for leptoquarks decaying into the b tau final state is performed using Run 2 proton-proton collision data from the Large Hadron Collider, corresponding to an integrated luminosity of 139 fb(-1) at root s = 13TeV recorded by the ATLAS detector. The benchmark models considered in this search are vector leptoquarks with electric charge of 2/3e and scalar leptoquarks with an electric charge of 4/3e. No significant excess above the Standard Model prediction is observed, and 95% confidence level upper limits are set on the cross-section times branching fraction of leptoquarks decaying into b tau. For the vector leptoquark production two models are considered: the Yang-Mills and Minimal coupling models. In the Yang-Mills (Minimal coupling) scenario, vector leptoquarks with a mass below 1.58 (1.35) TeV are excluded for a gauge coupling of 1.0 and below 2.05 (1.99) TeV for a gauge coupling of 2.5. In the case of scalar leptoquarks, masses below 1.28 (1.53) TeV are excluded for a Yukawa coupling of 1.0 (2.5). Finally, an interpretation of the results with minimal model dependence is performed for each of the signal region categories, and limits on the visible cross-section for beyond the Standard Model processes are provided.

A search for pair-produced scalar and vector leptoquarks decaying into quarks and leptons of different generations is presented. It uses the full LHC Run 2 (2015–2018) data set of 139 fb-1 collected with the ATLAS detector in proton–proton collisions at a centre-of-mass energy of √s̅ = 13 TeV. Scalar leptoquarks with charge -(1/3)e as well as scalar and vector leptoquarks with charge +(2/3)e are considered. All possible decays of the pair-produced leptoquarks into quarks of the third generation (t, b) and charged or neutral leptons of the first or second generation (e, μ, ν) with exactly one electron or muon in the final state are investigated. No significant deviations from the Standard Model expectation are observed. Upper limits on the production cross-section are provided for eight models as a function of the leptoquark mass and the branching ratio of the leptoquark into the charged or neutral lepton. In addition, lower limits on the leptoquark masses are derived for all models across a range of branching ratios. Two of these models have the goal of providing an explanation for the recent B-anomalies. In both models, a vector leptoquark decays into charged and neutral leptons of the second generation with a similar branching fraction. Lower limits of 1980 GeV and 1710 GeV are set on the leptoquark mass for these two models.

The exclusive production of pion pairs in the process pp→ ppπ+π- has been measured at s=7TeV with the ATLAS detector at the LHC, using 80μb-1 of low-luminosity data. The pion pairs were detected in the ATLAS central detector while outgoing protons were measured in the forward ATLAS ALFA detector system. This represents the first use of proton tagging to measure an exclusive hadronic final state at the LHC. A cross-section measurement is performed in two kinematic regions defined by the proton momenta, the pion rapidities and transverse momenta, and the pion–pion invariant mass. Cross-section values of 4.8±1.0(stat)-0.2+0.3(syst)μb and 9±6(stat)-2+2(syst)μb are obtained in the two regions; they are compared with theoretical models and provide a demonstration of the feasibility of measurements of this type.

Long-term weed control in gardens and arable areas is likely to be a potent selective force favouring precocious development of annual weed species. In an experiment with Stellaria media (L.) Vill., we grew progenies from open-pollinated seed of a number of seed-parents collected from 12 British populations of five habitat types. We raised plants in a temperate glasshouse and a garden plot, to see if plants from areas subject to weed control - gardens and arable fields - had a quicker rate of development from germination to flowering and fruiting than plants from habitats subject to less weed control (waysides) or no weeding pressure (seasonally exposed river sediments and bird colonies). Comparison of the behaviour of plants in the glasshouse and out-of-doors revealed a broadly similar pattern of behaviour. However, for some, but not all seed-parents, rate of development was different in the two sets of conditions. In conformity with hypothesis, plants from one of the gardens were quick to reproduce, but plants from Ness Botanic Garden and arable fields were more variable than expected. Plants from less well weeded and non-weeded sites did not conform to expectation. Plants from waysides were quick to reproduce, so too was much of the material from a bird colony on the island of Skomer. While some late-developing plants were detected from a second bird colony (Farne) and from exposed river sediments by the Tweed and Manifold, we found a small number of precocious and some intermediate individuals in the progeny of some seed-parents. It is possible that bird colonies and exposed river sediments are heterogeneous habitats, in which there are niches where 'native' variants with different rates of development are at a selective advantage. However, there is another explanation of our results. First, we discovered that, while some of the seed-parents were probably behaving as homogeneous lines for rate of development, others showed segregation, providing evidence that a degree of outcrossing is possible in populations of Stellaria. Secondly, there is evidence that human activities have led to habitat disturbance in and around the bird colonies and riverside vegetation we have studied. Our findings are consistent with the hypothesis that, gene flow by pollen and/or seed of precocious weedy plants has occurred in these man-disturbed sites, leading to different patterns of variation involving hybridization between 'introduced' precocious plants and 'native' slow-developing variants.

We have studied 27 triads of mother, daughter and grandmother for possible genetic influence on distal and proximal forearm bone density, measured by single photon absorptiometry. We found a significant correlation of bone density at the proximal forearm between the mothers and grandmothers (r = 0.499, P < 0.01). There was also a weak correlation between proximal forearm bone densities of mothers and daughters (r = 0.327, P < 0.1). Significant correlations were found between the three generations for grip strength, pedometry, height and triceps skinfold thickness. There was also significant correlation between mother and grandmother for alcohol intake. There was no correlation for contraceptive pill use, smoking, dietary calcium intake, body weight or body mass index. The study concludes that, although there are similarities in bone mineral content between the three generations, genetic factors cannot be conclusively proven to be the major determinant of bone density. Lifestyle and environmental factors may have a bearing on achieving the peak bone mass and subsequent development of osteoporosis.

Roughly 15% of black children in rural areas of southern Africa are carriers of the hepatitis B virus. The purpose of the present study was to determine the prevalence of chronic hepatitis B virus infection among urban black children born and growing up in Soweto. A total of 2364 children were studied, ranging in age from 3 to 19 years, and of these, 1319 (56%) were girls. The children were drawn from the highest and the lowest socioeconomic classes. Serum samples were tested for all hepatitis B virus markers as well as IgG antibody against hepatitis A virus. HBsAg was detected in 23 (0.97%) of the children, anti-HBc and anti-HBs together in 155 (6.6%), anti-HBc alone in 17 (0.7%), and anti-HBs alone in 72 (3%). Of the 2364 children, 2097 (88.5%) were negative for all hepatitis B virus markers. IgG antibody to hepatitis A virus was present in 175 (97%) of a sample of 179 children. There was no difference in prevalence of hepatitis B virus markers between children from the upper and lower socioeconomic classes. HBsAg was more common in boys (16 out of 1043 (1.5%) than girls (seven out of 1321 (0.57%), and the prevalence of all hepatitis B virus markers increased with age. The youngest carrier of hepatitis B virus was 7 years old. The remarkable difference in the hepatitis B virus carrier rate between urban and rural black children offers a unique opportunity to investigate the favourable influences operating in an urban environment to limit the prevalence of hepatitis B virus infection.