Thesis (M.P.H.)--University of Hong Kong, 2005.

The radiative capture cross section of a highly pure (99.999%), 6.125(2) grams 238U sample ((9.56±05)e-4 atoms/barn) has been measured in the 185 m flight path at the CERN neutron time-of-flight facility n_TOF in the energy range 0.3 eV-20 keV. The Total Absorption Calorimeter (TAC) detection system, an array of 40 BaF2 crystals, was used utilising the total absorption technique, where all the γ-rays from the capture cascades are detected. These data have undergone careful background subtraction, with special care being given to the background originating from neutrons scattered by the 238U sample. Pile-up and dead-time effects have been corrected for using an innovative correction method valid for variable high count rates within a complex detection system such as the TAC. The resulting capture yield has an uncertainty of up to 2.2% below 5 keV and up to 3.7% between 5 and 20 keV, in line with the accuracy requested in the NEA High Priority Request List. A resonance analysis has been performed up to 5 keV with the code SAMMY. Between 5 and 20 keV, the cross section is treated as unresolved and averaged. The results confirm the excellent quality of the most recent nuclear data evaluations within quoted uncertainties and suggest some improvements. In particular, these TAC data suggest a 2% increase in the average cross section in the energy range 2-9 keV and a 5% reduction in the energy range 9-20 keV.

This thesis presents MCNPX simulations of the SCANDAL set-up used at the Theodor Svedberg Laboratory for neutron scattering cross-section measurements. The thesis describes processes and data important for the upcoming off-line data analysis. In the experiment, neutrons scattered off the target are converted to protons which are stopped in scintillator crystals. The results of presented simulations include a description of the proton spectra in dependence of the neutron-to-proton conversion angle, calculation of the hit position gates and a study of the converter describing the role of its chemical composition and also the role of other plastic scintillator on the proton spectra. / QC 20100520

Introduction Maternal volume depletion at the time of caesarean section plays a role in ma- ternal and fetal outcome. Measuring uid volume status currently requires invasive monitors. It would be useful to determine biochemical measurements which would accurately determine uid volume status in these patients. We investigated the di erence in biochemical parameters of participants presenting for elective and urgent caesarean section at Chris Hani Baragwanath Hospital and made inferences about their uid volume status. We also sought to de- termine whether this difference in biochemical parameters if present could be linked to a potential difference in the intra-operative haemodynamic course as well as fetal outcome between the two groups. Method This was a prospective open-label observational cross-sectional pilot study. The sample was 54 participants, 27 elective and 27 urgent cases. Blood and urine samples were taken at the red line. Parameters from the blood samples were haematocrit, haemoglobin, sodium, urea, creatinine and plasma osmolality. Parameters from the urine samples were sodium, creatinine, osmolality and specific gravity. Intra-operatively, all participants received a standard spinal anaesthetic. Vari- ables measured intra-operatively were systolic, diastolic and mean arterial blood pressure, heart rate, highest level of block achieved as well as 1 and 5 minute Apgar scores of the newborn. The primary outcome variable was hypotension (mean arterial drop of more than 15% from the baseline). The secondary outcome variable were the Apgar scores of the infants. Results Urine specific gravity showed a trend towards statistical significance (mean, median, standard deviation for elective, urgent): 1.01, 1.010, 0.01 and 1.02, 1.015, 0.01 p = 0:06. The other biochemical parameteres displayed higher p- values. The average relative blood pressure change was -11,7% (median, standard de- viation) (-12.4, 11.1) for the elective group and -15.1% (-14.9, 15.1) for the urgent group p = 0:36. The relative blood pressure change to end point of study was -9.6% (-9, 12.7) for the elective group and -15.4% (-17, 17.6) for the urgent group p = 0:17. When comparing baseline blood pressure and heart rate measurements to the 10 minute end point measurements; 15 participants expe- rienced hypotension in the urgent group compared to 9 in the elective group p = 0:17. When comparing baseline blood pressure measurements to the av- erage at 2, 4, 6, 8, and 10 minute intervals; 13 participants from the urgent group experienced hypotension compared to 9 participants in the elective group p = 0:40. The average Apgar scores at 1 min were 8.89 (9,0.32) for the elective group and 8.37 (9,0.93) for the urgent group p = 0:01. Conclusion This was a pilot study and as such statistical signi cance between variables was not expected. However possible trends were identified to guide future investiga- tions. The higher incidence rate of hypotension in the urgent group showed such a trend towards signi cance as well as the higher urine specific gravity in the urgent group. We also noted that Apgar scores differed significantly between elective and urgent cases.

Electron Compton scattering is the best known fundamental QED process, however, a precision measurement of its cross section for a beam energy above 1 GeV has been lacking up to now. An updated high precision measurement of the neutral pion lifetime via the Primakoff effect (PrimEx-II) experiment was performed in Hall B of Jefferson Lab in 2010. The experiment used small angle coherent photoproduction of πO's in the Coulomb field of a nucleus, i.e. the Primakoff effect, to determine the lifetime with a precision of less than $1.5%. It therefore requires thorough understanding of the underlying systematic uncertainties. To facilitate that data for well known electromagnetic processes were taken concurrently with the photoproduction data. This analysis pertains to measuring the Compton scattering cross section, which occurs with similar kinematics to the primary process. The combination of the well established theory for this process with large collected statistics allowed to extract this cross section with high precision in an energy region of 4-5 GeV for 12C and 28Si targets. The results of this analysis will be presented.

The need for expert financial knowledge to lead school districts is paramount in education. The leader of a school district should possess knowledge and aptitude to generate funds to properly finance a school district. The management of school trust lands, also known as 16th section lands, provide a way for a school district with those lands to generate funds to supplement federal, state, and local funds. School trust lands were derived from the Northwest Ordinance of 1785 in which school districts were granted the 16th section in every township in new states in order to support public schools. The only research on the management of 16th section lands and the expenditure of revenue generated from 16th section lands has been conducted by foresters and economists. There is no research from an educator’s perspective on this subject. This research fills this gap in the research on school trust lands. The multiple case study method was used in this research. Four districts in Mississippi were selected based upon each district’s major resource of revenue. The superintendent, board president, and school financial officer were interviewed along with the personnel from the Mississippi Secretary of State’s office. Results from this study suggest that aggressive management is the key to the successful management of 16th section lands. Using the revenue generated from 16th section lands to create a fund balance (savings) and to supplement the overall general budget were general expenditures. Generally, 16th section lands should be managed aggressively to maximize revenue. The capital market theory should be applied to management of 16th section lands to assess risk, returns, and correlations on investments. For expenditure of revenue generated from 16th section lands, the revenue should be used as part of a long-range plan of financing schools in the districts. Revenue generated from 16th section lands have great potential to assist in the educational offerings of a district. Further research is needed in the area of municipal separate districts. Also, further research is needed in the area of increased revenue generated from 16th section lands as a possible correlation of decreased millage in districts.

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This thesis started with my memories of food and the activities that encompass it -- gathering, socializing, making and eating. These activities were explored in relation to the architectural fundamentals of form and section and through the function of a restaurant. Within a simple cubic form, four volumes developed into four unique dining areas -- bar, communal, main and family. Each space is an exploration of the various ways we gather around food. / Master of Architecture / Through the outlet of a restaurant, this thesis explores the various ways in which we gather around and eat food. This is achieved through the design and development of four interior spaces -- bar, communal, main and family.

Celà fait maintenant presque 50 ans qu'on a découvert que la section efficace totale proton-proton augmentait avec l’énergie, alors qu'on pensait précédemment qu'elle deviendrait asymptotiquement constante. Les incertitudes des mesures sur les rayons cosmiques effectuées à haute énergie ne permettent pas de déterminer la forme exacte de l'augmentation de la section efficace avec l’énergie.Le LHC au CERN à Genève fournit des collisions avec une énergie jamais atteinte dans un accélérateur de particule. L’énergie dans le centre de masse était 7 TeV en 2010 – 2011, 8 TeV en 2012 et atteindra 14 TeV dans un futur proche. Le détecteur ATLAS installé sur un des quatre points d'interaction du LHC, est utilisé pour collecter le résultat des collisions proton-proton. Son sous-détecteur ALFA, situé à 240 m du point d'interaction, est utilisé pour détecter les proton résultant des collisions élastiques. ALFA est donc capable, dans certaines conditions particulières de l'optique, de mesurer la section efficace totale et la pente nucléaire.Le travail effectué durant cette thèse a permit de mesurer σtot = 94.88 ± 0.12 stat ± 1.56syst mb et b = 19.45 ± 0.05stat ± 0.31syst GeV-2 à 7 TeV. / It is now nearly fifty years since total proton-proton (pp) cross sections have been found to grow with energy after it was believed for long time that they would become asymptotically constant . The uncertainties of the cosmic ray data, at high energy, do not allow to determine the exact growth with energy of the total cross section .The Large Hadron Collider (LHC) at CERN in Geneva has already delivered collisions with an energy never reached in a particle accelerator. The energy in the center of mass was 7 TeV (2010 – 2011) or 8 TeV (2012) and will ultimately reached 14 TeV in the near future. Thus, this will provide a good environment for a new precise measurement of the total pp cross section at this energy.The ATLAS detector installed in one of the four LHC interaction points is used to collect the result of the pp collisions. Its sub-detector ALFA located 240 m from the interaction point, is used to track protons resulting from elastic collisions.Therefore, within special beam optics conditions, ALFA is able to measure the total cross section and the nuclear slope. During this PhD the analysis performed on the first data led to σtot = 94.88 ± 0.12 stat ± 1.56syst mb and b = 19.45 ± 0.05stat ± 0.31syst GeV-2 at 7 TeV.

The photoabsorption cross sections of NO have been measured in the wavelength range 150~200nm, and the cross sections deviation from Beer-Lambert law due to the insufficient resolution of light source is discussed qualitatively. From the steady state approximation of quenching reactions, the pressure dependence of foreign gas on the ratio of absorption intensity to the fluorescence intensity is derived. Furthermore, the non-Stern-Volmer behaviors of the C2£S(n=0) state of NO were discussed by assuming the non-predissociated (J<9/2) and the predissociated (J>9/2) rotational levels following different quenching mechanisms.