5,984 research outputs found
Crucial contributors? Re-examining labour market impact and workplace-training intensity in Canadian trades apprenticeship
Get PDFCanadian apprenticeship policy has recently turned to direct subsidies for participants, including a federal tax incentive for employers. Some assumptions underlying the employer subsidy are: that apprenticeship training is a principal contributor to the skilled trades labour supply; that employers of apprentices typically incur high training cost and risks; and that in the absence of offsetting incentives, these would deter their participation. These assumptions are tested, using an analysis of 2006 census data and a series of 33 employer interviews. The census data reveal that, in 74 “skilled trades†occupations (NOC-S group H), the proportion of the labour force reporting an apprenticeship credential is 37%. When certificates granted to “trade qualifiers†are excluded from the total, registered apprenticeship certification is found to contribute roughly 25% of the skilled trades labour supply. A closer examination of the census data reveals strong inter-occupational differences in the certification rate and in the ratio of certified to less-than-certified workers, suggesting a de facto hierarchy of trades occupations. The interviews reveal sharp variations in employers’ workplace training efforts, challenging the twin suppositions that employers of apprentices are uniformly high contributors to skill formation, and that high training-related costs risks generally deter their participation. Differences in training behaviour are attributed to high-skill versus low-skill business strategies that in turn reflect differing product markets and regulatory constraints. Whatever the level of their training effort, all of the participating employers are able to minimize the training-related risks that have been cited as the principal rationale for employer subsidies. The paper argues for a more nuanced approach to skills policy and research in Canada, with greater attention to the diversity of actors’ strategic interactions with the training system.Apprenticeship, Skill, Trades, Training, Labour Supply, Canada
Development and leadership in computer-mediated collaborative groups
Get PDFComputer-mediated collaboration is an important feature of modern organisational and educational settings. Despite its ever increasing popularity, it is still commonly compared unfavourably with face-to-face collaboration because non-verbal and paralinguistic cues are minimal. Although research on face-to-face group collaboration is well documented, less is known about computer-mediated collaboration.
The initial focus of this thesis was an in-depth analysis of a case study of a computer-mediated collaborative group. The case study was a large international group of volunteer researchers who collaborated on a two-year research project using asynchronous communication (email). This case study was a window on collaborative dialogue in the early 1990s (1992-94) at a time when information and communication technologies were at an early stage of development.
After identifying the issues emerging from this early case study, another case study using technologies and virtual environments developed over the past decade, was designed to further understand how groups work together on a collaborative activity. The second case study was a small group of students enrolled in a unit of study at Murdoch University who collaborated on a series of nine online workshops using synchronous communication (chat room). This case study was a window on collaborative dialogue in the year 2000 when information and communication technologies had developed at a rate which few people envisioned in the early 90s.
The primary aim of the research described in this thesis was to gain a better understanding of how computer-mediated collaborative communities develop and grow. In particular, the thesis addresses questions related to the developmental and leadership characteristics of collaborative groups.
Internet research requires a set of assumptions relating to ontology, epistemology, human nature and methodological approach that differs from traditional research assumptions. A research framework for Internet research - Complementary Explorative Data Analysis (CEDA) - was therefore developed and applied to the two case studies.
The results of the two case studies using the CEDA methodology indicate that computer-mediated collaborative groups are highly adaptive to the aim of the collaborative task to be completed, and the medium in which they collaborate. In the organisational setting, it has been found that virtual teams can devise and complete a collaborative task entirely online. It may be an advantage, but it is certainly not mandatory to have preliminary face-to-face discussions. What is more important is to ensure that time is allowed for an initial period of structuration which involves social interaction to develop a social presence and eventually cohesiveness. In the educational setting, a collaborative community increases pedagogical effectiveness. Providing collaborative projects and interdependent tasks promotes constructivist learning and a strong foundation for understanding how to collaborate in the global workplace. Again, this research has demonstrated that students can collaborate entirely online, although more pedagogical scaffolding may be required than in the organisational setting. The importance of initial social interaction to foster a sense of presence and community in a mediated environment has also been highlighted.
This research also provided greater understanding of emergent leadership in computer-mediated collaborative groups. It was found that sheer volume of words does not make a leader but frequent messages with topic-related content does contribute to leadership qualities.
The results described in this thesis have practical implications for managers of virtual teams and educators in e-learning
The effectiveness of interventions to treat severe acute malnutrition in young children: a systematic review
No full textSevere acute malnutrition (SAM) arises as a consequence of a sudden period of food shortage and is associated with loss of a person’s body fat and wasting of their skeletal muscle. Many of those affected are already undernourished and are often susceptible to disease. Infants and young children are the most vulnerable as they require extra nutrition for growth and development, have comparatively limited energy reserves and depend on others. Undernutrition can have drastic and wide-ranging consequences for the child’s development and survival in the short and long term. Despite efforts made to treat SAM through different interventions and programmes, it continues to cause unacceptably high levels of mortality and morbidity. Uncertainty remains as to the most effective methods to treat severe acute malnutrition in young children.ObjectivesTo evaluate the effectiveness of interventions to treat infants and children aged < 5 years who have SAM.Data sourcesEight databases (MEDLINE, EMBASE, MEDLINE In-Process & Other Non-Indexed Citations, CAB Abstracts Ovid, Bioline, Centre for Reviews and Dissemination, EconLit EBSCO and The Cochrane Library) were searched to 2010. Bibliographies of included articles and grey literature sources were also searched. The project expert advisory group was asked to identify additional published and unpublished references.Review methodsPrior to the systematic review, a Delphi process involving international experts prioritised the research questions. Searches were conducted and two reviewers independently screened titles and abstracts for eligibility. Inclusion criteria were applied to the full texts of retrieved papers by one reviewer and checked independently by a second. Included studies were mapped to the research questions. Data extraction and quality assessment were undertaken by one reviewer and checked by a second reviewer. Differences in opinion were resolved through discussion at each stage. Studies were synthesised through a narrative review with tabulation of the results.ResultsA total of 8954 records were screened, 224 full-text articles were retrieved, and 74 articles (describing 68 studies) met the inclusion criteria and were mapped. No evidence focused on treatment of children with SAM who were human immunodeficiency virus sero-positive, and no good-quality or adequately reported studies assessed treatments for SAM among infants < 6 months old. One randomised controlled trial investigated fluid resuscitation solutions for shock, with none adequately treating shock. Children with acute diarrhoea benefited from the use of hypo-osmolar oral rehydration solution (H-ORS) compared with the standard World Health Organization-oral rehydration solution (WHO-ORS). WHO-ORS was not significantly different from rehydration solution for malnutrition (ReSoMal), but the safety of ReSoMal was uncertain. A rice-based ORS was more beneficial than glucose-based ORSs, and provision of zinc plus a WHO-ORS had a favourable impact on diarrhoea and need for ORS. Comparisons of different diets in children with persistent diarrhoea produced conflicting findings. For treating infection, comparison of amoxicillin with ceftriaxone during inpatient therapy, and routine provision of antibiotics for 7 days versus no antibiotics during outpatient therapy of uncomplicated SAM, found that neither had a significant effect on recovery at the end of follow-up. No evidence mapped to the next three questions on factors that affect sustainability of programmes, long-term survival and readmission rates, the clinical effectiveness of management strategies for treating children with comorbidities such as tuberculosis and Helicobacter pylori infection and the factors that limit the full implementation of treatment programmes. Comparison of treatment for SAM in different settings showed that children receiving inpatient care appear to do as well as those in ambulatory or home settings on anthropometric measures and response time to treatment. Longer-term follow-up showed limited differences between the different settings. The majority of evidence on methods for correcting micronutrient deficiencies considered zinc supplements; however, trials were heterogeneous and a firm conclusion about zinc was not reached. There was limited evidence on either supplementary potassium or nicotinic acid (each produced some benefits), and nucleotides (not associated with benefits). Evidence was identified for four of the five remaining questions, but not assessed because of resource limitation.LimitationsThe systematic review focused on key questions prioritised through a Delphi study and, as a consequence, did not encompass all elements in the management of SAM. In focusing on evidence from controlled studies with the most rigorous designs that were published in the English language, the systematic review may have excluded other forms of evidence. The systematic review identified several limitations in the evidence base for assessing the effectiveness of interventions for treating young children with severe acute malnutrition, including a lack of studies assessing the different interventions; limited details of study methods used; short follow-up post intervention or discharge; and heterogeneity in participants, interventions, settings, and outcome measures affecting generalisability.ConclusionsFor many of the most highly ranked questions evidence was lacking or inconclusive. More research is needed on a range of topic areas concerning the treatment of infants and children with SAM. Further research is required on most aspects of the management of SAM in children < 5 years, including intravenous resuscitation regimens for shock, management of subgroups (e.g. infants < 6 months old, infants and children with SAM who are human immunodeficiency virus sero-positive) and on the use of antibiotics.FundingThe National Institute for Health Research Technology Assessment programme.<br/
Modelling water quality for water distribution systems
No full textThis thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.Maintaining water quality in distribution systems has become a prominent issue in the study of water networks. This thesis concentrates on disinfectant and particle counts as two important indicators of water quality. The models discussed in this work are based on data collected by the author. The experimental set-up and procedure are described and observations of particle counts, particle counter size distributions, monochloramine as disinfectant, temperature, heterotrophic plate counts and epifluorescence microscopy counts are reported. A model of the response of particle counts to an increase in flow is developed. This model is obtained from specification derived from the data and assumptions, and is validated by its interpretability and its fit to data. A local shear-off density and an initial biofilm shedding profile were introduced and thus a linear model for this part of the water quality dynamics could be obtained. A procedure for the identification of the parameters of the local shear-off function and for the determination of the biofilm shedding profile is presented. This profile can be used to provide information about the status of the distribution system in terms of shear-off from the biofilm on the pipe walls. Monochloramine decay dynamics are investigated. The chlorine meter data is preprocessed with the help of titration data to correct meter drift. The data is then used in calibrating two different possible chlorine models: a model with a single decay coefficient and a model with bulk decay coefficient and wall demand (as used in Epanet). Important difficulties in identifying these parameters that come about because of the structure of the models are highlighted. Identified decay coefficients are compared and tested for flow, inlet chlorine and temperature dependence. The merits and limits of the approach to modelling taken in this work and a possible generalisation are discussed. The water industry perspective and an outlook are provided
Underlying-event studies with strange hadrons in pp collisions at s = 13 TeV with the ATLAS detector
No full textAbstract Properties of the underlying-event in pp interactions are investigated primarily via the strange hadrons K S 0 , Λ and Λ ¯ , as reconstructed using the ATLAS detector at the LHC in minimum-bias pp collision data at s = 13 TeV. The hadrons are reconstructed via the identification of the displaced two-particle vertices corresponding to the decay modes , Λ → π - p and Λ ¯ → π + p ¯ . These are used in the construction of underlying-event observables in azimuthal regions computed relative to the leading charged-particle jet in the event. None of the hadronisation and underlying-event physics models considered can describe the data over the full kinematic range considered. Events with a leading charged-particle jet in the range of 10 < p T ≤ 40 GeV are studied using the number of prompt charged particles in the transverse region. The ratio N ( Λ + Λ ¯ ) / N ( K S 0 ) as a function of the number of such charged particles varies only slightly over this range. This disagrees with the expectations of some of the considered Monte Carlo models
Review of particle physics
Get PDFThis biennial Review summarizes much of particle physics. Using data from previous editions, plus 2778 new measurements from 645 papers, we list, evaluate, and average measured properties of gauge bosons, leptons, quarks, mesons, and baryons. We also summarize searches for hypothetical particles such as Higgs bosons, heavy neutrinos, and supersymmetric particles. All the particle properties and search limits are listed in Summary Tables. We also give numerous tables, figures, formulae, and reviews of topics such as the Standard Model, particle detectors, probability, and statistics. Among the 108 reviews are many that are new or heavily revised including those on CKM quark-mixing matrix, Vud & Vus, Vcb & Vub, top quark, muon anomalous magnetic moment, extra dimensions, particle detectors, cosmic background radiation, dark matter, cosmological parameters, and big bang cosmology
An experimental study of solid particle motion in a turbulent liquid pipe flow
No full textAn experimental study of the motion of 100 micron diameter glass and stainless steel spheres in a fully developed turbulent liquid pipe flow was conducted. Furthermore, the liquid, water, was directed vertically downward through a 5.08 cm inside diameter plexiglas tube. One goal was to measure the turbulence properties of the particles in the r- plane with a previously developed axial viewing photographic technique. Another goal was to determine the effects of the inherent inhomogeneities of turbulent pipe flow on the results.Several particle turbulence properties were measured. Radial direction Lagrangian and Eulerian particle diffusion coefficients were obtained at Reynolds numbers (based on bulk velocity and pipe diameter) ranging from 15,700 to 141,000. Radial and azimuthal direction particle turbulence intensity profiles for both particles were obtained at Re = 16,000 and 72,000. The technique also permitted the radial and azimuthal direction particle acceleration to be measured.A new phenomenon was discovered which is the result of the inhomogeneities of turbulent pipe flow. It was found that under certain conditions, the particles that diffuse to the pipe wall may get temporarily or permanently trapped there. They get trapped in a patterned manner as well. Inhomogeneities were also found to affect the measured radial direction particle concentration and average velocity profiles, but only under certain conditions.Made available in DSpace on 2011-05-07T12:38:15Z (GMT). No. of bitstreams: 2
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A gate-level simulator for alpha-particle-induced transient faults
No full textMixed analog and digital mode simulators have been available for accurate alpha-particle-induced transient fault simulation. However, they are not fast enough to simulate a large number of transient faults on a relatively large circuit in a reasonable amount of time. This thesis describes a fast transient fault simulator which can evaluate the effects of alpha-particle hits or single event upsets (SEUs) in CMOS standard cell based synchronous sequential VLSI circuits. The speed comes from approximating the initial analog effects with gate level models, as well as using an improved transient fault simulation algorithm in a hierarchy of simulators. The simulator is shown to be between four to five orders of magnitude faster than a very accurate circuit simulator at the expense of some accuracy and some limitations on the types of circuits simulatable.Using this simulator, benchmark circuits have been tested for their behavior under alpha-particle injections. The experiments show that the one bit flip model is not a good model for injecting faults in highly fault tolerant systems. The experiments also show that at the pin level, no simple model exists which can mimic the behavior of the circuit hit with alpha particles.The simulator's usefulness is also shown in the development of a transient pulse tolerant D flip-flop (DFF). The tool is used to demonstrate the tradeoff between transient pulse tolerance and latch performance.Made available in DSpace on 2011-05-07T14:14:53Z (GMT). No. of bitstreams: 2
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Third-order charged particle beam optics
No full textThe motion of a charged particle through a magnetic field configuration can be described in terms of deviation from a certain ideal trajectory. One uses power series expansion of the phase-space coordinates to obtain the transfer matrices for a particular optical system.In this thesis we present a complete third-order theory of computing transfer matrices and apply it to magnetic elements in an accelerator beam-line. A particular attention is devoted to studying particles' orbits in an extended fringing field of a dipole magnet. Analytical solutions are obtained up to the third order in the formalism of the matrix theory. They contain form factors describing the fall-off pattern of the field. These form factors are dimensionless line integrals of the field strength and its derivative. There is one such integral in the first-order solution, two in the second, and nine in the third.An alternate way of describing charged particle optics is also presented. It is based on a Hamiltonian treatment and uses certain symplectic operators, which are defined in terms of Poisson brackets, to parametrize the transfer map of a system. We apply this approach to the fringing field problem and obtain a third-order solution. We furthermore show how to convert this solution into conventional transfer matrices by examining the connection between the non-canonical matrix theory and the Hamiltonian description.Made available in DSpace on 2011-05-07T11:54:57Z (GMT). No. of bitstreams: 2
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Review of particle properties
No full textThis biennial Review summarizes much of Particle Physics. Using data from previous editions, plus 2205 new measurements from 667 papers, we list, evaluate, and average measured properties of gauge bosons, leptons, quarks, mesons, and baryons. We also summarize searches for hypothetical particles such as Higgs bosons, heavy neutrinos, and supersymmetric particles. All the particle properties and search limits are listed in Summary Tables. We also give numerous tables, figures, formulae, and reviews of topics such as the Standard Model, particle detectors, probability, and statistics. This edition features expanded coverage of CP violation in B mesons and of neutrino oscillations. For the first time we cover searches for evidence of extra dimensions (both in the particle listings and in a new review). Another new review is on Grand Unified Theories. A booklet is available containing the Summary Tables and abbreviated versions of some of the other sections of this full Review. All tables, listings, and reviews (and errata) are also available on the Particle Data Group website: http://pdg.lbl.gov
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