Monoids in the mapping class group

In this article we survey, and make a few new observations about, the surprising connection between sub-monoids of mapping class groups and interesting geometry and topology in low-dimensions.Comment: 36 pages, 18 figure

Cabling, contact structures and mapping class monoids

In this paper we discuss the change in contact structures as their supporting open book decompositions have their binding components cabled. To facilitate this and applications we define the notion of a rational open book decomposition that generalizes the standard notion of open book decomposition and allows one to more easily study surgeries on transverse knots. As a corollary to our investigation we are able to show there are Stein fillable contact structures supported by open books whose monodromies cannot be written as a product of positive Dehn twists. We also exhibit several monoids in the mapping class group of a surface that have contact geometric significance.Comment: 62 pages, 32 figures. Significant expansion of exposition and more details on some argument

What will I be and how will I get there?: Examining the transition to adulthood among care leavers

Care leavers (adults formerly in foster care) are more likely to have negative outcomes in adulthood than non-fostered peers, especially in employment, earnings, and education (Courtney et al., 2011; Courtney et al., 2018; Pecora et al., 2005; Pecora et al., 2003). Success is determined by how well care leavers are able to demonstrate positive outcomes in these domains, but these domains are often defined by policy and research. Services provided by legislation focus on independent living skills to promote care leavers’ educational and employment opportunities in adulthood (Collins, 2014). However, little research has explored how care leavers themselves define success, determine their own goals, and use the services provided to meet their goals. Informed by the identity capital model (Côté, 2016b), this study answers the questions: 1) how do care leavers define success in their own words, 2) what self-defined goals did care leavers have as they transitioned out of care, and 3) what human, social, and cultural capital was available to help care leavers meet their goals at transition. Using a narrative approach, 15 care leavers were asked to offer their own definition of success, goals at transition, and provide details into what human, social, and cultural capital resources they had available to meet their goals. Findings indicate care leavers’ definitions of success demonstrate a focus on achievement, life satisfaction, and connection, and their goals are aligned with those determined by legislation and research. However, many had yet to achieve their transition goals by the time they aged out of aftercare services. This delay was based on systemic barriers that inhibited care leavers from building various capital during their time in care and during their transition to adulthood; these barriers are endemic to the child welfare system and posed a form of structural oppression in the lives of children and care leavers. This indicates a clear need for policy, practice, and research to determine better ways to provide services and reduce the impact of structural oppression within the child welfare system for future care leavers during their time in foster care, the transition from foster care, and early adulthood

Senior Recital:John Hansen, Horn

Kemp Recital Hall Sunday Evening November 8, 2003 2:00p.m

Potential of Unmanned Aerial Systems Imagery Relative to Landsat 8 Imagery in the Lower Pearl River Basin

Hurricane Isaac’s landfall on the coast of Louisiana spawned a hydrological research project between Mississippi State University (MSU), the Northern Gulf Institute (NGI), and the National Oceanic and Atmospheric Administration (NOAA) in the Lower Pearl River Basin (LPRB). Unmanned aerial systems data collection missions were scheduled every two months in the LPRB. This research provides a comparison between Landsat-8 imagery and corresponding UAS imagery with regards to the four remote sensing resolutions: spatial, spectral, radiometric, and temporal. Near-infrared (NIR) imagery from each platform was compared by land-water masks and statistical comparisons. A classification method known as natural breaks with Jenks Optimization determined threshold values between land and water for each image. Land-water masks revealed substantial differences between areas of land and water in comparing imagery. The overall difference in average land and water percentages between the two platforms was 1.77%; however, a larger percentage was 20.41% in a single comparison

Abnormalities of brain structure and lateralisation in schizophrenia

Researchers have proposed that schizophrenia is a disease related to abnormal cerebral lateralisation following findings of increased "schizophrenia-like" symptoms in left-hemisphere epileptics. Theories regarding abnormal brain structural asymmetries in schizophrenia suggest either ambiguous or extreme motor asymmetry. These theories are conceptually similar to ones proposed to explain non-right-handedness in normal subjects. In this thesis I objectively evaluate these hypotheses. Firstly, I critically survey the neuropsychological literature and find the evidence for lateralised cognitive deficit to be inconclusive. Next, a meta-analysis of studies reporting the finding of ventricular enlargement in schizophrenia is carried out and it is found that findings are highly influenced by methodological factors. A review of the literature concerning lateralised neuropathologies from brain imaging and postmortem studies similarly finds the evidence to be hindered by differences in experimental methodology. Furthermore, there is much disagreement between researchers regarding which asymmetries are empirically or theoretically meaningful. The next chapter concentrates exclusively with the experimental measurement of hand performance. The Annett pegboard, the Tapley and Bryden circle marking, and the Bishop square tracing tasks of hand performance are extended and used to test hand performance in normal subjects as a function of increasing task difficulty. Pursuit tracking is used to consider the Fourier spectrum and sub-components of relative hand performance. The differences between the hands on the conventional and tracking tasks are then subjected to factor analyses. Surprising results are obtained in which performance tasks show moderate-to-high internal reliability but correlate poorly with one another. Their relevance to handedness and motor research is then discussed. Schizophrenic hand preference is investigated in a meta-analytic assessment of studies reporting an increased incidence of non-dextral hand preference in schizophrenia. This is examined with respect to the definition and methods of measurement in these studies. Finally, the hand performance of schizophrenics is investigated. Testing hand performance, in conjunction with hand preference measures, allows for greater reliability in the evaluation of the notion of abnormal handedness in schizophrenia. Patients show poorer overall performance on all of the tasks, but show no significant differences in their degree of handedness as compared to normals. Conclusions are drawn that associations between abnormal handedness and disorders of brain structural asymmetry in schizophrenic patients are unlikely. Further implications for abnormalities of cerebral dominance and schizophrenia are considered

Better bound on the exponent of the radius of the multipartite separable ball

We show that for an m-qubit quantum system, there is a ball of radius asymptotically approaching kappa 2^{-gamma m} in Frobenius norm, centered at the identity matrix, of separable (unentangled) positive semidefinite matrices, for an exponent gamma = (1/2)((ln 3/ln 2) - 1), roughly .29248125. This is much smaller in magnitude than the best previously known exponent, from our earlier work, of 1/2. For normalized m-qubit states, we get a separable ball of radius sqrt(3^(m+1)/(3^m+3)) * 2^{-(1 + \gamma)m}, i.e. sqrt{3^{m+1}/(3^m+3)}\times 6^{-m/2} (note that \kappa = \sqrt{3}), compared to the previous 2 * 2^{-3m/2}. This implies that with parameters realistic for current experiments, NMR with standard pseudopure-state preparation techniques can access only unentangled states if 36 qubits or fewer are used (compared to 23 qubits via our earlier results). We also obtain an improved exponent for m-partite systems of fixed local dimension d_0, although approaching our earlier exponent as d_0 approaches infinity.Comment: 30 pp doublespaced, latex/revtex, v2 added discussion of Szarek's upper bound, and reference to work of Vidal, v3 fixed some errors (no effect on results), v4 involves major changes leading to an improved constant, same exponent, and adds references to and discussion of Szarek's work showing that exponent is essentially optimal for qubit case, and Hildebrand's alternative derivation for qubit case. To appear in PR