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Using data recorded by the CLEO II detector operating at the Upsilon(4S) resonance at the Cornell Electron Storage Ring, several properties of B mesons are measured using a partially reconstructed tag of the decay mode bar{B0} -> D*+ l- bar{nu}. Using 2.38 fb**{-1} of on-resonance data and the averaged B meson semileptonic branching fraction through inclusive lepton momentum spectrum obtained by previous CLEO analysis, we measure the B0 and B- semileptonic branching fraction to be (10.78 +/- 0.60 +/- 0.69)% and (10.25 +/- 0.57 +/- 0.65)% respectively, which yields the lifetime ratio tau_+/tau_0 = 0.950 +0.117-0.080 +0.091-0.068, assuming the equality of semileptonic partial branching width for bar{B0} and B-. With a larger dataset of 3.1 fb**{-1}, we measured the B0-bar{B0} mixing parameter chi_d to be 0.189 +/- 0.019 +/- 0.006. / Ph. D.

SNO+ is a liquid scintillator experiment whose physics goals include measurements of solar neutrinos, reactor anti-neutrinos, geo neutrinos and double beta decay. During an initial water phase, it will also search for invisible modes of nucleon decay. This thesis investigates methods of improving the detector's sensitivity to the baryon and lepton violating processes of neutrinoless double beta decay and invisible nucleon decay. It does this through an improved scintillator model, allowing the sensitivity of the detector with different loading techniques to be evaluated, through a new background rejection technique, capable of increasing the active volume of the detector, and with the development of improved position fitters, achieving resolutions of approximately 10 cm in scintillator and 25 cm in water. The sensitivity of SNO+ to invisible modes of nucleon decay is explored, predicting, after one month of data, a limit of t > 1.38 x 10³⁰ years on the decay of neutrons and of t > 1.57 x 10³⁰ years on the decay of protons.

This dissertation reports on new information in the [beta minus] decay of the neutron-rich nucleus 81Zn, which populates states in its daughter nucleus 81Ga. This includes new [gamma]-ray transitions in the daughter nucleus, 81Ga, as well as a [beta]-delayed neutron branching ratio. This isotope was produced at the Holifield Radioactive Ion Beam Facility of Oak Ridge National Laboratory through the Isotope Separation Online technique. They are fission fragments from proton-induced fission on a uranium carbide target. These fission fragments are ionized and both mass and isotopically separated before arriving at the Low Energy Radioactive Ion Beam Spectroscopy Station (LeRIBSS). The [gamma]-ray and [beta] electron emissions from the decays are measured and analyzed in this work. A new [beta]-delayed neutron branching ratio is reported for this decay, which is in agreement with recent theoretical values. The core excited states in the daughter nucleus, 81Ga, populated through allowed Gamow-Teller decays are analyzed. A trend in core excited states with other N=50 isotones indicates an increasing gap between a deeply bound neutron hole and the valence neutron above the N=50 gap upon moving towards doubly magic 78Ni. This dissertation also reports on additions to the decay schemes of 79Zn and 80Zn decays. Their decay level schemes have been expanded upon and an improved picture of the total allowed Gamow-Teller decay strength is known from 79Zn to 81Zn. This work presents an improved, albeit still incomplete, picture of the energy of states populated through Gamow-Teller decays from below to above the N=50 shell gap in zinc isotopes.

White and brown-rot fungi damage wood by production of enzymes that attack the structural components. The objective of this study was to characterize decay related genes and proteins that are expressed on three different wood types undergoing decay over 18 months. Variation in gene expression, presence of decay enzymes and proteins were determined for untreated pine (non-resistant), western red cedar (naturally durable), and alkaline copper quaternary (ACQ) treated pine (chemically resistant) exposed in a soil decay bed test. Decay was assessed by visual decay ratings, dynamic modulus of elasticity (MOE), and microscopy. There were no significant differences in decay between cedar and ACQ-treated pine over the 18 month period. However, there were significant differences in decay between pine and cedar and between pine and ACQtreated pine. The fungal mycelia penetrated the cell walls of pine and were continually observed over 18 months, but were not observed in cedar or ACQ-treated pine. Basidiomycetes containing decay genes lignin peroxidase (Lip), manganese peroxidase (Mnp), and laccase (Lcc) were detected on pine and ACQ-treated pine which also a greater diversity of fungi had compared to cedar. Phlebia radiata specific-lignin peroxidase and manganese peroxidase genes were expressed approximately equally on pine and ACQ-treated pine at most sampling times. The expression of P. radiata specific Lcc was higher on ACQ-treated pine than untreated pine. No basidiomycete genes were expressed and only a few basidiomycetes were identified on cedar, which also showed little decay. ACQ-treated pine also showed little decay, however basidiomycetes were present and active. Proteins were first detected on pine and ACQ-treated pine at 6 months and continued to increase through 18 months, but were not detected on cedar until 14 months exposure. There were greater numbers of total proteins on pine than on cedar and ACQ-treated pine at each time period. Decay genes were only found on pine but not on cedar and ACQ-treated pine. Additionally, the types of proteins and their score were different among the three wood types. From these results, the natural durability of cedar reduced the wood decay community and its activities. It appears that ACQ-treated wood did not stop the production of the decay enzymes but the chemical treatment did inhibit the effectiveness of the wood decay genes.

This dissertation describes the approach taken in measuring two neutrino double beta decay of Cd-116 to the ground state of Sn-116 and in searching for the effective Majorana neutrino mass by placing a lower limit on the half-life for neutrinoless double beta decay of Cd-116 using the powerful technique of a combined tracking chamber and calorimeter with the NEMO-3 detector. The description of the detector, its natural background contamination, and the tools used to perform the analysis are discussed. The single electron channel was used to identify source foil contamination from [beta]-emitters and the electron-gamma channel was used to confirm the previous measurements of Tl-208 and Bi-214 contaminations in the source foil. Using these backgrounds, the two neutrino double beta decay half-life of Cd-116 was measured for the single states dominance hypothesis and the higher states dominance hypothesis. The final data set was defined to be data from Phrase One and Phase Two for the medium and low activity regions. Using 1471 days of data, the values of the half-life for the single data dominance hypothesis and the higher states dominance hypothesis were found. / text

No description available.

Thesis (PhD)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: Reported claims of a solar neutrino influence on radioactive β - -decay rates prompted a series of three long term measurements that were carried out at the Koeberg nuclear power plant North of Cape Town to investigate the mirror reaction of reactor antineutrinos with a β + - source. The β + -emitter 22Na was exposed to a changing reactor antineutrino flux of the order of ~1012 cm-2 s -1 through the various phases of reactor operation, from off to on or vice versa, to investigate the antineutrino effect on its decay rate. 22Na sources were placed on the face of or inside a scintillation detector while γ-ray energy spectra were measured at source-toreactor-core distances of 17 m and 23 m for reactor unit #1 and unit #2 respectively. The analytical method employed uses ratios of the net-peak count rates of the photopeaks in the γ- ray energy spectra while the antineutrino flux changes during the various phases of reactor operation. These ratios reduce some potential systematic factors such as dead time, but should also remain constant during all phases of reactor operation and be independent of antineutrino flux if antineutrinos have no significant effect on the decay rate of 22Na. Measurement series 1 employed a LaBr3(Ce) detector. Results indicated an effect between reactor-off and –on corresponding to an antineutrino interaction cross section upper limit of the order of barns, assuming that antineutrinos are indeed the cause. Subsequently, two confirmation measurements were performed using a normal (cylindrical) NaI(Tl) detector as well as a NaI(Tl) well-counter. Results of these two measurements did not indicate any correlation with the reactor status. Measurements series 3 proved to be the most sensitive measurement for detecting changes in the decay rate of 22Na and an upper limit of ~10-25 cm 2 was estimated for the cross section of antineutrinos interacting with 22Na. This upper limit is one order of magnitude smaller compared to measurements series 1 and two orders of magnitude smaller compared to measurement series 2. It is also one of magnitude smaller than the effect reported by Jenkins et al. and two orders of magnitude smaller than observed by de Meijer et al. at the Delft reactor. Considering the systematic effects encountered during each measurement series we find no significant evidence for antineutrinos affecting β + -decay in 22Na. / AFRIKAANSE OPSOMMING: Berigte bewerings van son-afkomstige neutrinos se invloed op β - -verval het gelei tot drie lang termyn metings wat uitgevoer is by die Koeberg kernkrag stasie Noord van Kaapstad om die spieëldbeeld reaksie van antineutrinos met ‘n β + -bron te ondersoek. Die 22Na β + -bron is blootgestel aan ‘n veranderende reaktor antineutrino vloed van die order ~1012 cm -2 s -1 soos die reaktor deur verskeie fases van operasie gaan, vanaf afgeskakel na aangeskakel of omgekeerd, om die effek van antineutrinos op die bron se vervaltempo te ondersoek. 22Na bronne was teen die voorkant of binne ‘n sintillator detektor geplaas terwyl γ-straal energie spektra gemeet was by bron-tot-reaktor kern afstande van 17 m en 23 m vir reaktor eenheid #1 en #2 afsonderlik. Die analitiese metode gebruik verhoudings van die netto-piek teltempos van die fotopieke in die γ-straal energie spektra terwyl die antineutrino vloed verander tydens verskeie fases van reaktor operasie. Hierdie verhoudings verminder sekere potensiële systematiese effekte soos dooietyd en moet konstant bly tydens alle fases van reaktor operasie en moet ook onafhanklik wees van die antineutrino vloed indien antineutrinos geen effek het op die vervaltempo van 22Na nie. Die eerste reeks metings het gebruik gemaak van ‘n LaBr3(Ce) detektor. Resultate het ‘n effek getoon tussen reaktor-af en reaktor-aan wat ooreenstem met ‘n boonste limiet vir die interaksie kansvlak van antineutrinos met grootteorde van barns, indien antineutrinos wel die oorsaak is. Twee reekse van opvolgende metings is uitgevoer wat gebruik gemaak het van ‘n gewone (silindriese) NaI(Tl) detektor asook ‘n NaI(Tl) put detektor. Resultate van hierdie metings het geen korrelasie met die reaktor status gewys nie. Die derde reeks metings was die sensitiefste om veranderinge in die verval tempo van 22Na te wys en ‘n boonste limiet vir die interaksie kansvlak van antineutrinos op 22Na was beraam as ~10-25 cm 2 . Hierdie boonste limiet is een grootteorde kleiner in vergelyking met reeks 1 en twee grootteordes kleiner as reeks 2. Dit is ook een grootteorde kleiner as die waarde van Jenkins et al. en twee grootteordes kleiner as wat de Meijer et al. berig het by die Delft reaktor. In agneming van die systematise probleme wat ondervind was tydens die drie reeks metings vind ons geen beduidende effek van antineutrinos op die vervaltempo van 22Na nie.

ARS2 is a member of the nuclear cap-binding complex (CBC) that is critical for a number of RNA processing pathways. The emerging model is that ARS2 acts as a master regulator of RNAPII transcript maturation by bringing capped RNA substrates together with the appropriate processing machinery. ARS2 is essential for early mammalian development but it remains unclear precisely how ARS2 functions in stem and progenitor cell maintenance and differentiation. The purpose of this study was to answer basic questions about the localization and function of ARS2 in muscle progenitor cells. Here I describe the localization of ARS2 in proliferating myoblasts and post-mitotic differentiating myotubes and show that disruption of ARS2 expression levels by knockdown or overexpression results in impaired myogenic differentiation. I also discovered a new isoform of ARS2 that is localized exclusively in the cytoplasm and found preliminary evidence that ARS2 is required for nonsense-mediated decay (NMD). This study includes the first evidence that an ARS2 isoform is expressed in the cytoplasm and opens the door for the discovery of new ARS2 functions beyond its reported roles in the nucleus. / Graduate

This thesis describes a search for the rare radiative decay of a B meson to two photons. where the charged congugate mode is implied throughout. These decays are highly suppressed in the Standard Model where the branching fraction is expected to be of order 10^-8. In some new physics scenarios this could be enhanced by up to an order of magnitude to 10^-7. Therefore an observation of a significant signal above the Standard Model prediction could be a sign of new physics. The search for this rare decay was performed using the data collected with the BaBar detector at the SLAC National Accelerator Laboratory PEP-II storage ring operating at the Upsilon(4S) resonance. The analysis uses a dataset with an integrated luminosity of 425.7 fb-1 corresponding to 467 million BB pairs. A signal yield of 21.3 +12.8 -11.8 events with a significance of 1.88 sigma was measured using an unbinned extended maximum likelihood fit. An upper limit on the branching fraction is set at the 90% confidence level of less than 3.2 times 10^-7. This is about two times more stringent than the best upper limit of less than 6.2 times 10^-7 published by the Belle collaboration. / text