The world makers : one centre's approach to technology education with infants and toddlers

Infants and toddlers are surrounded by technology. They observe and explore technological artefacts and the uses of them on a daily basis. Despite this, there is little research to guide teachers about what the technological interests, understandings and capabilities of infants and toddlers might be and how they might be supported and extended. Technology education is a relative/y new curriculum area and it has not yet been included in the literary discourse about infant and toddler educational programmes. This study aims to examine what the teachers at one childcare centre identify as the technology interests, understandings and capabilities of a small group of infants and toddlers. Video footage was taken of the infants and toddlers at work and play and segments were then shown to individual teachers during interviews. The children's assessment portfolios were examined and the teachers and families were invited to contribute further information. The sum total of this data was used to analyse and reflect on particular episodes of video footage. The technological interests, understandings and capabilities of both the children and the adults were seen to be integrally linked to the temporal, physical and interpersonal environments of the centre

Tertiary education policy: a case study of student interpretations and personal effects for school leavers : a thesis presented in partial fulfilment of the requirements for the degree of Master of Arts in Education, Education Department, Massey University

Tertiary education policy is produced in a political context with the purpose of bringing about specific planned effects. The manner in which individuals actively process policy messages within their own particular context of experience results in policy effects at times differing from projected effects for various individuals. The thesis is based on a case study research project which examines the decision making processes of ten senior secondary school students from a single secondary school in their final year of schooling. The research aims to identify the messages that students receive from Government tertiary policy and to evaluate the extent to which these messages are incorporated into individual decision making. Additional factors which influence the post school destination eventually chosen by students are also discussed. The personal effects of tertiary education policy differ from its ostensibly stated effects for most students. It is suggested that principles of 'fairness' and 'greater personal choice' are not realised for the majority of students. Instead, the position, disposition and communication effects of each student are shown to influence their post school destination. While all students respond to aspects of policy in the manner that it is envisaged that they would, the agency of individuals in making rational decisions within the structures of their own circumstances means that policy effects differ for each student

A Bayesian self-clustering analysis of the highest energy cosmic rays detected by the Pierre Auger Observatory

Cosmic rays (CRs) are protons and atomic nuclei that flow into our Solar system and reach the Earth with energies of up to ~10^21 eV. The sources of ultra-high energy cosmic rays (UHECRs) with E >~ 10^19 eV remain unknown, although there are theoretical reasons to think that at least some come from active galactic nuclei (AGNs). One way to assess the different hypotheses is by analysing the arrival directions of UHECRs, in particular their self-clustering. We have developed a fully Bayesian approach to analyzing the self-clustering of points on the sphere, which we apply to the UHECR arrival directions. The analysis is based on a multi-step approach that enables the application of Bayesian model comparison to cases with weak prior information. We have applied this approach to the 69 highest energy events recorded by the Pierre Auger Observatory (PAO), which is the largest current UHECR data set. We do not detect self-clustering, but simulations show that this is consistent with the AGN-sourced model for a data set of this size. Data sets of several hundred UHECRs would be sufficient to detect clustering in the AGN model. Samples of this magnitude are expected to be produced by future experiments, such as the Japanese Experiment Module Extreme Universe Space Observatory (JEM-EUSO).Comment: 10 pages, 4 figures; accepted in MNRA

A Bayesian analysis of the 69 highest energy cosmic rays detected by the Pierre Auger Observatory

The origins of ultra-high energy cosmic rays (UHECRs) remain an open question. Several attempts have been made to cross-correlate the arrival directions of the UHECRs with catalogs of potential sources, but no definite conclusion has been reached. We report a Bayesian analysis of the 69 events from the Pierre Auger Observatory (PAO), that aims to determine the fraction of the UHECRs that originate from known AGNs in the Veron-Cety & Veron (VCV) catalog, as well as AGNs detected with the Swift Burst Alert Telescope (Swift-BAT), galaxies from the 2MASS Redshift Survey (2MRS), and an additional volume-limited sample of 17 nearby AGNs. The study makes use of a multi-level Bayesian model of UHECR injection, propagation and detection. We find that for reasonable ranges of prior parameters, the Bayes factors disfavour a purely isotropic model. For fiducial values of the model parameters, we report 68% credible intervals for the fraction of source originating UHECRs of 0.09+0.05-0.04, 0.25+0.09-0.08, 0.24+0.12-0.10, and 0.08+0.04-0.03 for the VCV, Swift-BAT and 2MRS catalogs, and the sample of 17 AGNs, respectively

The Formation and Evolution of Massive Black Holes

The past 10 years have witnessed a change of perspective in the way astrophysicists think about massive black holes (MBHs), which are now considered to have a major role in the evolution of galaxies. This appreciation was driven by the realization that black holes of millions solar masses and above reside in the center of most galaxies, including the Milky Way. MBHs also powered active galactic nuclei known to exist just a few hundred million years after the Big Bang. Here, I summarize the current ideas on the evolution of MBHs through cosmic history, from their formation about 13 billion years ago to their growth within their host galaxies.Comment: Review for Science Special Issue on black hole

Clarifying the Hubble constant tension with a Bayesian hierarchical model of the local distance ladder

Estimates of the Hubble constant, H0, from the local distance ladder and from the cosmic microwave background (CMB) are discrepant at the ∼3-σ level, indicating a potential issue with the standard ΛCDM cosmology. A probabilistic (i.e., Bayesian) interpretation of this tension requires a model comparison calculation, which in turn depends strongly on the tails of the H₀ likelihoods. Evaluating the tails of the local H₀ likelihood requires the use of non-Gaussian distributions to faithfully represent anchor likelihoods and outliers, and simultaneous fitting of the complete distance ladder dataset to ensure correct uncertainty propagation. We have hence developed a Bayesian hierarchical model of the full distance ladder that does not rely on Gaussian distributions and allows outliers to be modelled without arbitrary data cuts. Marginalizing over the full ∼3000-parameter joint posterior distribution we find H0 = (72.72 ± 1.67) km s¯¹ Mpc¯¹ when applied to the outlier-cleaned Riess et al. (2016) data, and (73.15 ± 1.78) km s¯¹ Mpc¯¹ with SN outliers reintroduced (the pre-cut Cepheid dataset is not available). Using our precise evaluation of the tails of the H0 likelihood, we apply Bayesian model comparison to assess the evidence for deviation from ΛCDM given the distance-ladder and CMB data. The odds against ΛCDM are at worst ∼10:1 when considering the Planck Collaboration (2016b) data, regardless of outlier treatment, considerably less dramatic than naïvely implied by the 2.8-σ discrepancy. These odds become ∼60:1 when an approximation to the more-discrepant Planck Collaboration (2016c) likelihood is included