Pre-Big Bang Scenario on Self-T-Dual Bouncing Branes

We consider a new class of 5-dimensional dilatonic actions which are invariant under T-duality transformations along three compact coordinates, provided that an appropriate potential is chosen. We show that the invariance remains when we add a boundary term corresponding to a moving 3-brane, and we study the effects of the T-duality symmetry on the brane cosmological equations. We find that T-duality transformations in the bulk induce scale factor duality on the brane, together with a change of sign of the pressure of the brane cosmological matter. However, in a remarkable analogy with the Pre-Big Bang scenario, the cosmological equations are unchanged. Finally, we propose a model where the dual phases are connected through a scattering of the brane induced by an effective potential. We show how this model can realise a smooth, non-singular transition between a pre-Big Bang superinflationary Universe and a post-Big Bang accelerating Universe.Comment: 18 pages, minor typos corrected, Sec. 2 expanded with more details on the self-T-dual background, Sec.4 and 5 revised accordingly. Version to appear on JCA

Combustion and operating characteristics of spark-ignition engines

The spark-ignition engine turbulent flame propagation process was investigated. Then, using a spark-ignition engine cycle simulation and combustion model, the impact of turbocharging and heat transfer variations or engine power, efficiency, and NO sub x emissions was examined

Detection of K+ mesons in segmented electromagnetic calorimeters

The combination of the CrystalBall and TAPS electromagnetic calorimeters were installed in the MAMI A2 hall in 2003. Here they are able to detect the reaction products from photo-induced reactions in combination with the Glasgow photon tagger. In the last two years the MAMI facility was upgraded from 885 MeV to 1.5 GeV, the A2 photon tagger underwent a similar upgrade crossing the threshold for strangeness photoproduction. For the CrystalBall this created a new challenge, to identify K+ mesons above the large background from other charged hadrons, in a situation where the detector setup does not benefit from a magnetic field to help separate particle species. These proceedings outline a novel technique which uses the decay products of the K+ as a strangeness tag

Digital measurement of lightning impulse parameters using curving fitting algorithms

This paper describes the application of curve fitting algorithms to aid the evaluation of lightning impulse parameters. A number of popular curve fitting algorithms have been evaluated and compared. Investigations using the genetic algorithm and other optimisation methods for the purpose of curve fitting have also been carried out and will be described

Addressing the Safety and Criminal Exploitation of Vulnerable Young People: Before, During and After COVID-19 and Lockdown

This chapter is discussing the intersection of what is arguably an epidemic, and a pandemic, both of which can be fatal. In recent years there has been an epidemic in youth violence and crime, particularly in East London, and in the London Borough of Newham, where knife crime cases and youth knife injuries in particular have been consistently higher than comparator boroughs and London as a whole between 2013 and 2017. The chapter discusses in some detail the pre-pandemic Newham Keeping Safe (hereafter NKS) intervention aimed at vulnerable teenagers, proposing how this type of intervention could be adapted to the changing conditions of COVID-19 restrictions, and exploring the broader psychosocial implications for future interventions that aim to reduce the criminal exploitation of vulnerable young people, as we ‘open up’, or, at least, travel through new sets of changing conditions and restrictions. Such an endeavour requires that we reflect on what future levels of social distancing combined with more digital connections and practices could mean. Future interventions, we argue, need to include a reflection on the complex needs of children and families, and fathom the impact of interventions and their future post-COVID-19

Characterization of 40-Gbit/s pulses generated using a lithium niobate modulator at 1550 nm using frequency resolved optical gating

The characteristics of 40-Gbit/s pulses generated by exploiting the nonlinear characteristics of a Mach-Zender Lithium Niobate modulator are presented. A high spectral resolution frequency resolved optical gating apparatus has been developed to allow for the complete characterization of the intensity and phase of these pulses. The use of these measurements to simplify the design and optimization of an 80-Gbit/s pulse source, based on this 40-Gbit/s source followed by a nonlinear fiber compressor and multiplexer, is also demonstrated

Today's problems with the evaluation methods of full lightning impulse parameters as described in IEC 60060-1

In this paper the present problems with the evaluation methods for lightning impulse parameters, as defined in IEC 60060-1, are described. Also the current practice of evaluation in many laboratories world-wide, that is obtained by a questionnaire, is presented. Some of the work performed up the present time and the initial conclusions are reported, then some recommendations are made for future work

SurF: an innovative framework in biosecurity and animal health surveillance evaluation

Surveillance for biosecurity hazards is being conducted by the New Zealand Competent Authority, the Ministry for Primary Industries (MPI) to support New Zealand's biosecurity system. Surveillance evaluation should be an integral part of the surveillance life cycle, as it provides a means to identify and correct problems and to sustain and enhance the existing strengths of a surveillance system. The surveillance evaluation Framework (SurF) presented here was developed to provide a generic framework within which the MPI biosecurity surveillance portfolio, and all of its components, can be consistently assessed. SurF is an innovative, cross‐sectoral effort that aims to provide a common umbrella for surveillance evaluation in the animal, plant, environment and aquatic sectors. It supports the conduct of the following four distinct components of an evaluation project: (i) motivation for the evaluation, (ii) scope of the evaluation, (iii) evaluation design and implementation and (iv) reporting and communication of evaluation outputs. Case studies, prepared by MPI subject matter experts, are included in the framework to guide users in their assessment. Three case studies were used in the development of SurF in order to assure practical utility and to confirm usability of SurF across all included sectors. It is anticipated that the structured approach and information provided by SurF will not only be of benefit to MPI but also to other New Zealand stakeholders. Although SurF was developed for internal use by MPI, it could be applied to any surveillance system in New Zealand or elsewhere

Early motherhood: A qualitative study exploring the experiences of African Australian teenage mothers in greater Melbourne, Australia

BACKGROUND: Motherhood is a significant and important aspect of life for many women around the globe. For women in communities where motherhood is highly desired, motherhood is considered crucial to the woman's identity. Teenage motherhood, occurring at a critical developmental stage of teenagers' lives, has been identified as having adverse social and health consequences. This research aimed to solicit the lived experiences of African Australian young refugee women who have experienced early motherhood in Australia. METHODS: This qualitative research used in-depth interviews. The research methods and analysis were informed by intersectionality theory, phenomenology and a cultural competency framework. Sixteen African born refugee young women who had experienced teenage pregnancy and early motherhood in Greater Melbourne, Australia took part in this research. Interviews were audio recorded, transcribed and data analysed using thematic content analysis. Ethics approval for this research was granted by Victoria University Human Research Ethics committee. RESULTS: Motherhood brings increased responsibilities, social recognition, and a sense of purpose for young mothers. Despite the positive aspects of motherhood, participants faced challenges that affected their lives. Most often, the challenges included coping with increased responsibilities following the birth of the baby, managing the competing demands of schooling, work and taking care of a baby in a site of settlement. The young mothers indicated they received good support from their mothers, siblings and close friends, but rarely from the father of their baby and the wider community. Participants felt that teenage mothers are frowned upon by their wider ethnic communities, which left them with feelings of shame and embarrassment, despite the personal perceived benefits of achieving motherhood. CONCLUSIONS: We propose that service providers and policy makers support the role of the young mothers' own mother, sisters, their grandmothers and aunts following early motherhood. Such support from significant females will help facilitate young mothers' re-engagement with education, work and other aspects of life. For young migrant mothers, this is particularly important in order to facilitate settlement in a new country and reduce the risk of subsequent mistimed pregnancies. Service providers need to expand their knowledge and awareness of the specific needs of refugee teen mothers living in 'new settings'