The interplay of multiplicity and effective energy for (multi) strange hadron production in pp collisions at the LHC

The enhanced production of strange hadrons in heavy-ion collisions relative to that in minimum-bias pp collisions is historically considered one of the first signatures of the formation of a deconfined quark-gluon plasma. At the LHC, the ALICE experiment observed that the ratio of strange to non-strange hadron yields increases with the charged-particle multiplicity at midrapidity, starting from pp collisions and evolving smoothly across interaction systems and energies, ultimately reaching Pb-Pb collisions. The understanding of the origin of this effect in small systems remains an open question. This thesis presents a comprehensive study of the production of $K^{0}_{S}$, $\Lambda$ ($\bar{\Lambda}$) and $\Xi^{-}$ ($\bar{\Xi}^{+}$) strange hadrons in pp collisions at $\sqrt{s}$ = 13 TeV collected in LHC Run 2 with ALICE. A novel approach is exploited, introducing, for the first time, the concept of effective energy in the study of strangeness production in hadronic collisions at the LHC. In this work, the ALICE Zero Degree Calorimeters are used to measure the energy carried by forward emitted baryons in pp collisions, which reduces the effective energy available for particle production with respect to the nominal centre-of-mass energy. The results presented in this thesis provide new insights into the interplay, for strangeness production, between the initial stages of the collision and the produced final hadronic state. Finally, the first Run 3 results on the production of $\Omega^{\pm}$ ($\bar{\Omega}^{+}$) multi-strange baryons are presented, measured in pp collisions at $\sqrt{s}$ = 13.6 TeV and 900 GeV, the highest and lowest collision energies reached so far at the LHC. This thesis also presents the development and validation of the ALICE Time-Of-Flight (TOF) data quality monitoring system for LHC Run 3. This work was fundamental to assess the performance of the TOF detector during the commissioning phase, in the Long Shutdown 2, and during the data taking period

The general relativistic two body problem

The two-body problem in General Relativity has been the subject of many analytical investigations. After reviewing some of the methods used to tackle this problem (and, more generally, the N-body problem), we focus on a new, recently introduced approach to the motion and radiation of (comparable mass) binary systems: the Effective One Body (EOB) formalism. We review the basic elements of this formalism, and discuss some of its recent developments. Several recent comparisons between EOB predictions and Numerical Relativity (NR) simulations have shown the aptitude of the EOB formalism to provide accurate descriptions of the dynamics and radiation of various binary systems (comprising black holes or neutron stars) in regimes that are inaccessible to other analytical approaches (such as the last orbits and the merger of comparable mass black holes). In synergy with NR simulations, post-Newtonian (PN) theory and Gravitational Self-Force (GSF) computations, the EOB formalism is likely to provide an efficient way of computing the very many accurate template waveforms that are needed for Gravitational Wave (GW) data analysis purposes.Comment: 43 pages, 4 figures, to appear in the Brumberg Festschrift, edited by S. M. Kopeikein, and to be published by de Gruyter, Berlin, 2014. arXiv admin note: substantial text overlap with arXiv:1212.316

Effective psychological therapy for PTSD changes the dynamics of specific large-scale brain networks

In posttraumatic stress disorder (PTSD), re-experiencing of the trauma is a hallmark symptom proposed to emerge from a de-contextualised trauma memory. Cognitive therapy for PTSD (CT-PTSD) addresses this de-contextualisation through different strategies. At the brain level, recent research suggests that the dynamics of specific large-scale brain networks play an essential role in both the healthy response to a threatening situation and the development of PTSD. However, very little is known about how these dynamics are altered in the disorder and rebalanced after treatment and successful recovery. Using a data-driven approach and fMRI, we detected recurring large-scale brain functional states with high temporal precision in a population of healthy trauma-exposed and PTSD participants before and after successful CT-PTSD. We estimated the total amount of time that each participant spent on each of the states while being exposed to trauma-related and neutral pictures. We found that PTSD participants spent less time on two default mode subnetworks involved in different forms of self-referential processing in contrast to PTSD participants after CT-PTSD (mtDMN+ and dmDMN+) and healthy trauma-exposed controls (only mtDMN+). Furthermore, re-experiencing severity was related to decreased time spent on the default mode subnetwork involved in contextualised retrieval of autobiographical memories, and increased time spent on the salience and visual networks. Overall, our results support the hypothesis that PTSD involves an imbalance in the dynamics of specific large-scale brain network states involved in self-referential processes and threat detection, and suggest that successful CT-PTSD might rebalance this dynamic aspect of brain function

The influence of marketing communications on the youth's adoption of m-payments in KwaZulu-Natal.

Doctoral Degree. University of KwaZulu-Natal, Durban.There has been poor subscription and usage of m-payments in the recent past in South Africa (RSA), especially with the failure of Vodacom M-Pesa and MTN Mobile Money. Presumably, this is attributed to a lack of knowledge on the functionality and benefits of such services and the fact that ‘cash is king’. This study places integrated marketing communications (IMC) at the centre of the adoption of m-payments, as it plays a key role in informing users on the effect of reducing user uncertainties and risks as knowledge structures are built. The study adopted a survey research design to determine the influence of IMC on the adoption and use of mpayments among the youth in KwaZulu-Natal. The questionnaire utilised in the study adopted scale items from constructs embedded within the Unified Technology Acceptance and Use Theory 2 (UTAUT2) and the communication performance construct, to obtain quantitative data. Quota sampling was used to draw a sample of 383 respondents from three institutions of higher learning located in the cities of Durban and Pietermaritzburg. With a 73% response rate, analysis of the gathered data was carried out using descriptive and inferential techniques. Hypotheses were tested using multiple linear regression, Student’s t Test, exploratory factor analysis, confirmatory factor analysis and structural equation modelling, so as to refine and develop a conceptual model. The structural model was found to have a good fit with all but two hypotheses-linked paths being statistically significant and hence supported. IMC measured in the form of communication performance was found to have a strong direct positive impact on the risk factors (functional risk, social influence, price value and facilitating conditions). Communication performance had the greatest positive impact on price value, suggesting that the youth are a rational user market segment with a need for utilitarian motivation within m-payment purchase or use situations, regardless of gender. This study explored the relationship between IMC and innovation adoption, thereby extending the body of knowledge in a multidisciplinary field of marketing and information technology, producing a model that may be used in probing m-payments use behaviour from a marketing perspective. Key words: Integrated marketing communications, mobile payments, structural equation modelling, technology adoption, youth market.List of Exhibits on page xvi of thesis

Predictive solvent and anti-solvent selection method for pharmaceutical and biological products and intermediates.

Doctoral Degree. University of KwaZulu-Natal, Durban.Abstract available in pdf

Town of Chesterville Maine Ordinances

Ordinances Cover: Board of Appeal; Dog; e911 Addressing; Flood Plain; General Assistance; Hazardous Waste; Land Use; Parking; Recall Elected Official; Recycling; Shoreland Zoning; Town Clerk & Tax Collector Appointment; Treasurer Appointment; Water Qualit

An investigation of bacterial composition and biofilm structure in mixed-community bioanodes

PhD ThesisMicrobial fuel cells (MFC) are devices that convert chemical energy in soluble organic matter into electrical energy. They can be used for wastewater treatment coupled with energy production as well as for sensing, hydrogen production, electrosynthesis and metal recovery. Implementing these technologies is hindered by low current production. Currently, little is known about anodic communities regarding growth, electrode coverage, bacterial composition, biofilm structure, metabolism and how are they affected by operational factors. Such knowledge is needed to engineer MFCs that can overcome current limitations. The subject of the present study is the mixed-community bioanode. The effects of light, anode-tocathode surface ratio (A/C), substrate composition and anode potential on bioanodes were investigated. Two types of substrates were used: the first was based on sodium acetate and the second was a synthetic wastewater which simulated the chemical composition of real wastewater. First bioanodes were studied in presence and absence of light. A different set of bioanodes were grown at 9 different A/C ratios in single-chamber MFCs. Another set of bioanodes were grown in half-cells at 3 different anode potentials (-400 mV, -200 mV and 0 mV vs Ag/AgCl). The development of anodic biofilms and their long-term dynamics were investigated using a multi-anode reactor which allowed for better replication of running conditions. Geobacter was identified in all bioanodes but its abundance was highly variable and dependent on running conditions. Over time the bacterial composition of bioanodes under constant conditions continuously changed during the first 33 days but stabilised by the 67th day. Bioanodes fed on acetate had higher cell counts, Geobacter percentage, and current output than bioanodes fed on synthetic wastewater. Light exposure decreased coulombic efficiency by almost 14 times and favored growth of Rhodopseudomonas species in the detriment of Geobacter. Abundance of Geobacter increased with anode potential when fed on acetate (from 609.98 106 cells/gram at -400 mV to 5212.38 106 cells/gram at 0 mV) but decreased when fed on synthetic wastewater (from 200.6 106 cells/gram at -400 mV to 49 106 cells/gram at 0 mV). Current density and Geobacter density decreased by an order of magnitude when A/C ratio was varied from 1:12 to 1:1 but remained relatively constant when A/C was increased further to 8:1. Uneven biomass coverage on bioanodes and a decrease of biofilm volume with depth inside bioanodes were observed suggesting that anodes were only partially used by electrigenic bacteria. Results reported here have important implications for future reactor designs, on the use of three-dimensional bioanodes and on long-term applications of Microbial Fuel Cells

Synthesis and Characterization of Functional Thin Ultra-Low Density Coatings Inside Hollow Spheres

Uniform coatings on the inner surface of hollow spheres have applications in optical devices, time- or site-controlled drug release, and heat storage devices. Spherical shells that contain a thin layer of ultra-low density polymer foam have also attracted attention in the inertial confinement fusion community where they can be used to bring dopants for diagnostics and nuclear physics experiments in direct contact with the deuterium-tritium (DT) fuel or to study new ignition regimes by enabling the formation of uniform liquid DT fuel layers. The uniformity of these coatings is often critical for the application performance and, therefore, requires precise understanding and control over the coating process and its parameters. Rather than trying to fabricate free-standing foam shells, as it was reproducibly done in the fusion community, a new approach can be explored: using prefabricated hollow spherical shells as molds to cast concentric, thin-walled, low-density foam layers using sol-gel chemistry. For this purpose, a molecular precursor solution is inserted into the shell through a tiny hole using a pressure gradient filling process, where it transforms into a high-viscosity polymer fluid and ultimately gels during rotation, creating a uniform gel layer. The remaining solvent is then removed from the shell via supercritical drying, leaving a uniform, ultra-low density aerogel layer in the sphere. This thesis presents a detailed step by step study on the synthesis and characterization of functional, ultra-low density coatings inside hollow spheres using this novel approach. It will describe how polymer-based sol–gel chemistry can be utilized to achieve ultra-low density coatings and report on in situ real-time radiography experiments that provide critical spatiotemporal information about the distribution of fluids inside hollow spheres during uniaxial rotation. An approach to remove the solvent from the gel in the shell without damaging the coated layer is presented and lastly a methodology on casting doped polymer films on the inside of spherical capsules is developed