2,542 research outputs found

    Secondary school pupils' preferences for different types of structured grouping practices

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    The aim of this paper is to explore pupilsā€™ preferences for particular types of grouping practices an area neglected in earlier research focusing on the personal and social outcomes of ability grouping. The sample comprised over 5,000 year 9 pupils (aged 13-14 years) in 45 mixed secondary comprehensive schools in England. The schools represented three levels of ability grouping in the lower school (years 7 to 9). Pupils responded to a questionnaire which explored the types of grouping that they preferred and the reasons for their choices. The majority of pupils preferred setting, although this was mediated by their set placement, type of school, socio-economic status and gender. The key reason given for this preference was that it enabled work to be matched to learning needs. The paper considers whether there are other ways of achieving this avoiding the negative social and personal outcomes of setting for some pupils

    Tensions of Integration in Professional Formation: Investigating Development of Engineering Students\u27 Social and Technical Perceptions

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    Tensions of Integration in Professional Formation: Investigating Development of Engineering Students\u27 Social and Technical PerceptionsTwenty-first century engineers face incredible challenges and opportunities, many of which aresocially complex, transcending the traditional ā€œtechnicalā€ boundaries of engineering. Thetechnology produced by engineers must not only function as predicted by mathematical andtheoretical models but must also operate beneficially and seamlessly in complex social contexts.In this sense, engineers must embody an integrated social and technical ā€“ or sociotechnical ā€“identity rather than a dualistic social/technical one.A growing body of scholarship has discussed how dominant cultures of engineering shapestudentsā€™ and professionalsā€™ understandings of social and technical dimensions of their work.Further, engineering education research has advanced understanding of how engineering identityis formed by external, structural forces. Yet, from a psychological perspective, we know littleabout how engineering students come to perceive and embody their identities as engineers,especially in relation to social and technical dimensions of these identities. Thus, we organizedthis study around the following research questions.RQ0: How do students psychologically experience identity trajectories of becoming engineers?RQ1: How do students perceive the social and technical features of engineering identity?RQ2: How do students internally experience their identities as engineers, particularly with regard to social and technical dimensions of these identities?RQ3: How do social and technical perceptions of their engineering identity develop and change in the course of the engineering curriculum or in the transition to the workplace?To respond to these research questions, we have conducted two longitudinal studies usinginterpretative phenomenological analysis (IPA). One study focused on graduating seniors as theytransitioned into the workplace, and the second study focused on first-year students transitioningto engineering degree coursework. These investigations produced robust and nuancedunderstanding of studentsā€™ engineering identity trajectories throughout and beyond thecurriculum. These findings are being leveraged in order to provide our initial understanding in athematic analysis on sophomore engineering students.Thus far, the findings of the investigation highlight the complexity of becoming both engineers,specifically by demonstrating a somewhat contradictory relationship between what participantsperceived to be engineering and how they actually embodied an engineering-self. They furtherdemonstrate the manifold ways that participants realized and prioritized identities outside ofengineering and how these multiple selves interacted in ways that affected their engineeringidentities. Additionally, findings for both male and female groups suggest that somepsychological patterns might be related to gender. In sum, the findings depict a complex pictureof engineering-students-turned-engineers as whole persons. By focusing on how engineeringidentity development is embodied, the findings generate multiple theoretical insights that bearrelevance for engineering education research and provocative implications that bear significancefor engineering educators, students, and employers

    Multi-wavelength Observations of Dusty Star Formation at Low and High Redshift

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    This paper examines what can be learned about high-redshift star formation from the small fraction of high-redshift galaxies' luminosities that is emitted at accessible wavelengths. We review and quantify empirical correlations between bolometric luminosities produced by star formation and the UV, mid-IR, sub-mm, and radio luminosities of galaxies in the local universe. These correlations suggest that observations of high-redshift galaxies at any of these wavelengths should constrain their star-formation rates to within 0.2--0.3 dex. We assemble the limited evidence that high-redshift galaxies obey these locally calibrated correlations. The characteristic luminosities and dust obscurations of galaxies at z ~ 0, z ~ 1, and z ~ 3 are reviewed. After discussing the relationship between the high-redshift populations selected in surveys at different wavelengths, we calculate the contribution to the 850um background from each. The available data show that a correlation between star-formation rate and dust obscuration L_dust/L_UV exists at low and high redshift. This correlation plays a central role in the major conclusion of this paper: most star formation at high redshift occurred in galaxies with 1 < L_dust/L_UV < 100 similar to those that host the majority of star formation in the local universe and to those that are detected in UV-selected surveys. (abridged)Comment: Scheduled for publication in ApJ v544 Dec 2000. Significant changes to section 4. Characteristic UV and dust luminosities of star-forming galaxies at redshifts z~0, z~1, and z~3 presented. Existence of extremely obscured galaxies more clearly acknowledged. Original conclusions reinforced by the observed correlation between bolometric luminosity and dust obscuration at 0<z<

    Intercomparison of field measurements of nitrous acid (HONO) during the SHARP campaign

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    Because of the importance of HONO as a radical reservoir, consistent and accurate measurements of its concentration are needed. As part of SHARP (Study of Houston Atmospheric Radical Precursors), time series of HONO were obtained by six different measurement techniques on the roof of the Moody Tower at the University of Houston. Techniques used were long path differential optical absorption spectroscopy (DOAS), stripping coil-visible absorption photometry (SC-AP), long path absorption photometry (LOPAPĀ® ), mist chamber/ion chromatography (MC-IC), quantum cascade-tunable infrared laser differential absorption spectroscopy (QC-TILDAS), and ion drift-chemical ionization mass spectrometry (ID-CIMS). Various combinations of techniques were in operation from 15 April through 31 May 2009. All instruments recorded a similar diurnal pattern of HONO concentrations with higher median and mean values during the night than during the day. Highest values were observed in the final 2 weeks of the campaign. Inlets for the MC-IC, SC-AP, and QC-TILDAS were collocated and agreed most closely with each other based on several measures. Largest differences between pairs of measurements were evident during the day for concentrations ~100 parts per trillion (ppt). Above ~ 200 ppt, concentrations from the SC-AP, MC-IC, and QC-TILDAS converged to within about 20%, with slightly larger discrepancies when DOAS was considered. During the first 2 weeks, HONO measured by ID-CIMS agreed with these techniques, but ID-CIMS reported higher values during the afternoon and evening of the final 4 weeks, possibly from interference from unknown sources. A number of factors, including building related sources, likely affected measured concentrations

    Experts' Judgments of Management Journal Quality:An Identity Concerns Model

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    Many lists that purport to gauge the quality of journals in management and organization studies (MOS) are based on the judgments of experts in the field. This article develops an identity concerns model (ICM) that suggests that such judgments are likely to be shaped by the personal and social identities of evaluators. The model was tested in a study in which 168 editorial board members rated 44 MOS journals. In line with the ICM, respondents rated journal quality more highly to the extent that a given journal reflected their personal concerns (associated with having published more articles in that journal) and the concerns of a relevant ingroup (associated with membership of the journalā€™s editorial board or a particular disciplinary or geographical background). However, judgesā€™ ratings of journals in which they had published were more favorable when those journals had a low-quality reputation, and their ratings of journals that reflected their geographical and disciplinary affiliations were more favorable when those journals had a high-quality reputation. The findings are thus consistent with the view that identity concerns come to the fore in journal ratings when there is either a need to protect against personal identity threat or a meaningful opportunity to promote social identity

    Modelling stochastic bivariate mortality

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    Stochastic mortality, i.e. modelling death arrival via a jump process with stochastic intensity, is gaining increasing reputation as a way to represent mortality risk. This paper represents a first attempt to model the mortality risk of couples of individuals, according to the stochastic intensity approach. On the theoretical side, we extend to couples the Cox processes set up, i.e. the idea that mortality is driven by a jump process whose intensity is itself a stochastic process, proper of a particular generation within each gender. Dependence between the survival times of the members of a couple is captured by an Archimedean copula. On the calibration side, we fit the joint survival function by calibrating separately the (analytical) copula and the (analytical) margins. First, we select the best fit copula according to the methodology of Wang and Wells (2000) for censored data. Then, we provide a sample-based calibration for the intensity, using a time-homogeneous, non mean-reverting, affine process: this gives the analytical marginal survival functions. Coupling the best fit copula with the calibrated margins we obtain, on a sample generation, a joint survival function which incorporates the stochastic nature of mortality improvements and is far from representing independency.On the contrary, since the best fit copula turns out to be a Nelsen one, dependency is increasing with age and long-term dependence exists

    Ethnic In-Group Favoritism Among Minority and Majority Groups: Testing the Self-Esteem Hypothesis Among Preadolescents

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    The self-esteem hypothesis in intergroup relations, as proposed by social identity theory (SIT), states that successful intergroup discrimination enhances momentary collective self-esteem. This hypothesis is a source of continuing controversy. Furthermore, although SIT is increasingly used to account for childrenā€™s group attitudes, few studies have examined the hypothesis among children. In addition, the hypothesisā€™s generality makes it important to study among children from different ethnic groups. The present study, conducted among Dutch and Turkish preadolescents, examined momentary collective self-feelings as a consequence of ethnic group evaluations. The results tended to support the self-esteem hypothesis. In-group favoritism was found to have a self-enhancing effect among participants high in ethnic identification. This result was found for ethnic majority (Dutch) and minority (Turkish) participants.

    Polarized Single Top Production at Leptonic Colliders from Broken R Parity Interactions Incorporating CP Violation

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    The contribution from the R parity violating interactions in the associated production of a top quark with a charm antiquark is examined for high energy leptonic colliders. We concentrate on the reactions associated with the semileptonic top decay. A set of characteristic dynamical distributions for the signal events is evaluated and the results contrasted against those from the standard model W-boson pair production background. Next, we turn to a study of a CP-odd observable, associated with the top spin, which leads to an asymmetry in the energy distribution of the emitted charged leptons for the pair of CP-conjugate final states, blĖ‰Ī½cĖ‰b \bar l \nu \bar c and bĖ‰lĪ½Ė‰c \bar b l \bar \nu c . A non vanishing asymmetry arises from a CP-odd phase, embedded in the R parity violating coupling constants, through interference terms between the R parity violating amplitudes at both the tree and loop levels.Comment: revtex file. 17 pages. 7 postscript figures. 1 table. The revised version includes an estimate of experimental uncertainties. Submitted to Phys. Rev.

    Can Doubly Strange Dibaryon Resonances be Discovered at RHIC?

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    The baryon-baryon continuum invariant mass spectrum generated from relativistic nucleus + nucleus collision data may reveal the existence of doubly-strange dibaryons not stable against strong decay if they lie within a few MeV of threshold. Furthermore, since the dominant component of these states is a superposition of two color-octet clusters which can be produced intermediately in a color-deconfined quark-gluon plasma (QGP), an enhanced production of dibaryon resonances could be a signal of QGP formation. A total of eight, doubly-strange dibaryon states are considered for experimental search using the STAR detector (Solenoidal Tracker at RHIC) at the new Relativistic Heavy Ion Collider (RHIC). These states may decay to Lambda-Lambda and/or proton-Cascade-minus, depending on the resonance energy. STAR's large acceptance, precision tracking and vertex reconstruction capabilities, and large data volume capacity, make it an ideal instrument to use for such a search. Detector performance and analysis sensitivity are studied as a function of resonance production rate and width for one particular dibaryon which can directly strong decay to proton-Cascade-minus but not Lambda-Lambda. Results indicate that such resonances may be discovered using STAR if the resonance production rates are comparable to coalescence model predictions for dibaryon bound states.Comment: 28 pages, 5 figures, revised versio
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