Catalogue Search | MBRL
Are you sure you want to remove the book from the shelf?
{{itemTitle}}
212
result(s) for
"Hilton, Matt"
Sort by:
Worst fear
\"When the body of Tess Grey's former university roommate is found on a rocky Maine beach, having fallen from the cliffs above, the initial verdict is suicide. But why would Chelsea Grace, who was terrified of heights, have chosen to end her life in a way that invoked her very worst fear? Tess determines to find out.\"--Publisher's description.
Book
The effect of shyness on children's formation and retention of novel word–object mappings
This study set out to examine whether shyness, an aversion to novelty and unfamiliar social situations, can affect the processes that underlie early word learning. Twenty-four-month-old children (n =32) were presented with sets of one novel and two familiar objects, and it was found that shyer children were less likely to select a novel object as the referent of a novel label. Furthermore, not-shy children then showed evidence of retaining these novel mappings, but shy children did not. These findings suggest that shy children's aversion to novelty and to the unfamiliar context can impact on their word learning.
Journal Article
Early assembly of the most massive galaxies
The current consensus is that galaxies begin as small density fluctuations in the early Universe and grow by in situ star formation and hierarchical merging. Stars begin to form relatively quickly in sub-galactic-sized building blocks called haloes which are subsequently assembled into galaxies. However, exactly when this assembly takes place is a matter of some debate. Here we report that the stellar masses of brightest cluster galaxies, which are the most luminous objects emitting stellar light, some 9 billion years ago are not significantly different from their stellar masses today. Brightest cluster galaxies are almost fully assembled 4-5 billion years after the Big Bang, having grown to more than 90 per cent of their final stellar mass by this time. Our data conflict with the most recent galaxy formation models based on the largest simulations of dark-matter halo development. These models predict protracted formation of brightest cluster galaxies over a Hubble time, with only 22 per cent of the stellar mass assembled at the epoch probed by our sample. Our findings suggest a new picture in which brightest cluster galaxies experience an early period of rapid growth rather than prolonged hierarchical assembly.
Journal Article
A GMRT Narrowband vs. Wideband Analysis of the ACT−CL J0034.4+0225 Field Selected from the ACTPol Cluster Sample
Low frequency radio observations of galaxy clusters are a useful probe of the non-thermal intracluster medium (ICM), through observations of diffuse radio emission such as radio halos and relics. Current formation theories cannot fully account for some of the observed properties of this emission. In this study, we focus on the development of interferometric techniques for extracting extended, faint diffuse emissions in the presence of bright, compact sources in wide-field and broadband continuum imaging data. We aim to apply these techniques to the study of radio halos, relics and radio mini-halos using a uniformly selected and complete sample of galaxy clusters selected via the Sunyaev-Zel’dovich (SZ) effect by the Atacama Cosmology Telescope (ACT) project, and its polarimetric extension (ACTPol). We use the upgraded Giant Metrewave Radio Telescope (uGMRT) for targeted radio observations of a sample of 40 clusters. We present an overview of our sample, confirm the detection of a radio halo in ACT−CL J0034.4+0225, and compare the narrowband and wideband analysis results for this cluster. Due to the complexity of the ACT−CL J0034.4+0225 field, we use three pipelines to process the wideband data. We conclude that the experimental spam wideband pipeline produces the best results for this particular field. However, due to the severe artefacts in the field, further analysis is required to improve the image quality.
Journal Article
A Multiwavelength Dynamical State Analysis of ACT-CL J0019.6+0336
In our study, we show a multiwavelength view of ACT-CL J0019.6+0336 (which hosts a radio halo), to investigate the cluster dynamics, morphology, and ICM. We use a combination of XMM-Newton images, Dark Energy Survey (DES) imaging and photometry, SDSS spectroscopic information, and 1.16 GHz MeerKAT data to study the cluster properties. Various X-ray and optical morphology parameters are calculated to investigate the level of disturbance. We find disturbances in two X-ray parameters and the optical density map shows elongated and axisymmetric structures with the main cluster component southeast of the cluster centre and another component northwest of the cluster centre. We also find a BCG offset of ∼950 km/s from the mean velocity of the cluster, and a discrepancy between the SZ mass, X-ray mass, and dynamical mass (MX,500 and MSZ,500 lies >3σ away from Mdyn,500), showing that J0019 is a merging cluster and probably in a post-merging phase.
Journal Article
CHARITY, DECOLONIZATION AND DEVELOPMENT: THE CASE OF THE STAREHE BOYS SCHOOL, NAIROBI
The Starehe Boys School in Nairobi is one of the undoubted success stories of post-independence Kenya. It was founded in 1959 by Geoffrey Griffin, a disillusioned former British army officer. Appalled by the atrocities committed by both sides during the Mau Mau Emergency (1952-60), Griffin refused to renew his commission and worked instead to care for juveniles caught up in the crisis. Initially with just two tin sheds on a piece of waste ground not far from the slums in the Eastlands district of the city, the school began as a club which took in destitute boys made homeless either through the death of their parents or their forced migration. Here, Hilton explores why the school became the object of the hopes and imaginations of a really quite extraordinary cast of characters.
Journal Article
Temperament and Early Word Learning: The Effect of Shyness on Referent Selection and Retention
The current thesis examined individual differences that can impact on the disambiguation and learning of novel word meanings, focusing on the effects of shyness, defined as an aversion to novelty in social situations (Putnam, Gartstein & Rothbart, 2006). A systematic pattern of attention during labeling is crucial in supporting children's novel word disambiguation (Halberda, 2006), and in determining whether these novel word meanings will be learned (Axelsson, Churchley & Horst, 2012). This thesis hypothesized that shyness affects novel word disambiguation and learning by modulating attention during labeling. This thesis showed that shy children did not reliably select a novel object as the referent of a novel label, while less-shy children did. Crucially, only less-shy children showed evidence of learning the novel label-referent mappings (Paper 1). However, these differences were only apparent in an unfamiliar environment (Paper 2), likely because shy children attended much more to features of the unfamiliar environment than lessshy children, which reduced their attention to the objects during labeling. Examination of children's eye-gaze during novel object labeling supported the conclusion that shyness exerts an effect on word learning via attention. Shy children did not demonstrate robust disengagement from the novel object during labeling (Paper 3), which meant that competitor objects could not be ruled out as referents, a critical process in determining whether a novel word-referent mapping will be formed (Mather & Plunkett, 2009). Furthermore, shy children's bias to attend to faces (Brunet et al., 2009) reduced their attention to potential referents during labeling (Paper 4). This thesis thus argues that shyness impacts on word disambiguation and learning by modulating the attentional processes that support these abilities, clearly demonstrating that shyness affects one of the earliest stages of language development: word learning.
Dissertation
A Multiwavelength Dynamical State Analysis of ACT-CLJ0019.6+0336
In our study, we show a multiwavelength view of ACT-CL J0019.6+0336 (which hosts aradio halo), to investigate the cluster dynamics, morphology, and ICM. We use a combination ofXMM-Newton images, Dark Energy Survey (DES) imaging and photometry, SDSS spectroscopicinformation, and 1.16 GHz MeerKAT data to study the cluster properties. Various X-ray and opticalmorphology parameters are calculated to investigate the level of disturbance. We find disturbancesin two X-ray parameters and the optical density map shows elongated and axisymmetric structureswith the main cluster component southeast of the cluster centre and another component northwest ofthe cluster centre. We also find a BCG offset of∼950 km/s from the mean velocity of the cluster, anda discrepancy between the SZ mass, X-ray mass, and dynamical mass (MX,500andMSZ,500lies>3σaway fromMdyn,500), showing that J0019 is a merging cluster and probably in a post-merging phase.
Journal Article
Evolution in cluster cores since z ~ 1
A large fraction of the stellar mass in galaxy clusters is thought to be contained in the diffuse low surface brightness intracluster light (ICL). Being bound to the gravitational potential of the cluster rather than any individual galaxy, the ICL contains much information about the evolution of its host cluster and the interactions between the galaxies within. However due its low surface brightness it is notoriously difficult to study. We present the first detection and measurement of the flux contained in the ICL at z ~ 1. We find that the fraction of the total cluster light contained in the ICL may have increased by factors of 2–4 since z ~ 1, in contrast to recent findings for the lack of mass and scale size evolution found for brightest cluster galaxies. Our results suggest that late time build-up in cluster cores may occur more through stripping than merging and we discuss the implications of our results for hierarchical simulations.
Journal Article
X-ray observations of the Zwicky 3146 galaxy cluster reveal a 3.5 keV excess
In this note, we present spectral fits of the well-documented sloshing cool-core cluster Zwicky 3146 (\\(z=0.291\\)), to test the existence of the highly speculated 3.5 keV line. We report excesses at \\(>3\\sigma\\) significance at \\(E=3.575\\) keV, yielding a flux \\(F = 8.73_{-2.22}^{+2.17}\\) \\(\\times 10^{-6}\\) photons cm\\(^{-2}\\) s\\(^{-1}\\), in \\textit{XMM-Newton}, and \\(E=3.55\\) keV, with a flux \\(F = 10.0_{-2.96}^{+3.05}\\) \\(\\times 10^{-6}\\) photons cm\\(^{-2}\\) s\\(^{-1}\\) in \\textit{Chandra}. We explore the possibility that the 3.5 keV excess is correlated to the presence of cold gas within the cluster, based on optical and sub-mm literature analyses. Following the launch of the X-ray Imaging and Spectroscopy Mission (XRISM), high resolution spectroscopy (\\(\\leq 7\\) eV) will reveal in unprecedented detail, the origin of this unidentified feature, for which Zwicky 3146 should be considered a viable target, due to the strength of the feature in two independent X-ray telescopes, opening a new window into plasma or charge exchange studies in galaxy clusters.
Paper