Identification of Parton Pairs in a Dijet Event and Investigation of Its Effects on Dijet Resonance Search

Being able to distinguish parton pair type in a dijet event could significantly improve the search for new particles that are predicted by the theories beyond the Standard Model at the Large Hadron Collider. To explore whether parton pair types manifesting themselves as a dijet event could be distinguished on an event-by-event basis, I performed a simulation based study considering observable jet variables. I found that using a multivariate approach can filter out about 80% of the other parton pairs while keeping more than half of the quark-quark or gluon-gluon parton pairs in an inclusive QCD dijet distribution. The effects of event-by-event parton pair tagging for dijet resonance searches were also investigated and I found that improvement on signal significance after applying parton pair tagging can reach up to 4 times for gluon-gluon resonances.Comment: 10 pages, 4 figure

SUSY Parameters Determination with ATLAS

The plan for mass and spin measurement of SUSY particles with the ATLAS detector is presented. The measurements of kinematical distributions, such as edges in the invariant mass of leptons and jets, could be used to constrain the model of SUSY that may be discovered at the LHC. Examples from a few points in the mSUGRA scenario are provided with an emphasis on measurements that can be conducted within the first few years of data taking.Comment: Submitted for the SUSY07 proceedings, 4 pages, LaTeX, 5 eps figures; resized figures to 4 page

Search for Supersymmetry Signatures at the LHC

Supersymmetry (SUSY) is one of the most interesting and comprehensively studied models for new physics beyond the Standard Model. If SUSY exists in nature the Large Hadron Collider will provide excellent opportunities to search for SUSY. SUSY discovery strategies of the ATLAS and CMS experiments are presented with a focus on early data. SUSY mass measurement techniques and determination of SUSY model parameters are also demonstrated.Comment: To be published in the proceedings of DPF-2009, Detroit, MI, July 2009, eConf C09072

Secondary metabolism of the forest pathogen Dothistroma septosporum : a thesis presented in the partial fulfilment of the requirements for the degree of Doctor of Philosophy (PhD) in Genetics at Massey University, Manawatu, New Zealand

Dothistroma septosporum is a fungus causing the disease Dothistroma needle blight (DNB) on more than 80 pine species in 76 countries, and causes serious economic losses. A secondary metabolite (SM) dothistromin, produced by D. septosporum, is a virulence factor required for full disease expression but is not needed for the initial formation of disease lesions. Unlike the majority of fungal SMs whose biosynthetic enzyme genes are arranged in a gene cluster, dothistromin genes are dispersed in a fragmented arrangement. Therefore, it was of interest whether D. septosporum has other SMs that are required in the disease process, as well as having SM genes that are clustered as in other fungi. Genome sequencing of D. septosporum revealed that D. septosporum has 11 SM core genes, which is fewer than in closely related species. In this project, gene cluster analyses around the SM core genes were done to assess if there are intact or other fragmented gene clusters. In addition, one of the core SM genes, DsNps3, that was highly expressed at an early stage of plant infection, was knocked out and the phenotype of this mutant was analysed. Then, evolutionary selection pressures on the SM core genes were analysed using the SM core gene sequences across 19 D. septosporum strains from around the world. Finally, phylogenetic analyses on some of the SM core genes were done to find out if these genes have functionally characterised orthologs. Analysis of the ten D. septosporum SM core genes studied in this project showed that two of them were pseudogenes, and five others had very low expression levels in planta. Three of the SM core genes showed high expression levels in planta. These three genes, DsPks1, DsPks2 and DsNps3, were key genes of interest in this project. But despite the different expression levels, evolutionary selection pressure analyses showed that all of the SM core genes apart from the pseudogenes are under negative selection, suggesting that D. septosporum might actively use most of its SMs under certain conditions. In silico predictions based on the amino acid sequences of the proteins encoded by SM core genes and gene cluster analyses showed that four of the SM core genes are predicted to produce known metabolites. These are melanin (DsPks1), cyclosporin (DsNps1), ferricrocin (DsNps2) and cyclopiazonic acid (DsHps1). Gene cluster analyses revealed that at least three of the D. septosporum SMs might be produced by fragmented gene clusters (DsPks1, DsNps1, DsNps2). This suggested that dothistromin might not be the only fragmented SM gene cluster in D. septosporum. According to phylogenetic analyses, some of the D. septosporum SM core genes have no orthologs among its class (Dothideomycetes), suggesting some of the D. septosporum SMs may be unique. One such example is the metabolite produced by DsNps3. Comparison of wild type and ΔDsNps3 D. septosporum strains showed that the ΔDsNps3 strain produces fewer spores, less hyphal surface network at an early stage of plant infection, and lower levels of fungal biomass in disease lesions compared to wild type, suggesting that the DsNps3 SM may be a virulence factor. Attempts to identify a metabolite associated with DsNps3, and to knockout another gene of key interest, DsPks2, for functional characterization were unsuccessful. Further work is required to confirm the gene clusters, characterise the SMs and their roles. However, the findings so far suggest that dothistromin is unlikely to be the only D. septosporum SM that is a virulence factor in since the DsNps3 SM also appears to be involved in virulence. Likewise the fragmented dothistromin cluster may not be the only one in the genome and there may be at least three more fragmented SM gene clusters

Minimum Wages, Market Inflexibilities, and Female Employment in Select OECD Countries

Using international and intertemporal variations in minimum wages, employment protection laws, minimum wage regulations and female work behavior within the OECD, empirical analysis provide evidence that higher minimum wages are associated with lower female labor force participation and employment. This association is more significant in countries with more stringent employment protection laws, lower female tertiary educational enrollment and higher fertility. In addition to the extensive margin analysis, it is shown that minimum wage levels are positively correlated with the ratio of part-time workers. That is, minimum wages are associated with not only lower participation and employment rates among women but also with higher marginalization of female work. This association is stronger in countries with more inflexible labor markets and less active labor market policies. Moreover, existence of a subminimum wage for youths implies further reduction of employment while increasing part-time job incidence for females, when the minimum wage increases.Labor market regulations, female work, minimum wage, OECD, time series data

FMR Study of Co/Ti Bilayer Thin Films

. We focused on the interaction between two ferromagnetic cobalt layers through a non-magnetic titanium layer. The magnetic properties of the structure were characterized by ferromagnetic resonance technique (FMR). The data were collected as a function of non-magnetic titanium layer thickness. Co/Ti multilayer (Ti (50 {\AA})/Co(45 {\AA})/Ti(2-40 {\AA})/Co(40 {\AA})/Ti(100 {\AA}))films were grown onto naturally oxidized p-type single crystal Si (100) substrate at UHV condition with magnetron sputtering system at room temperature. The thickness of Ti spacer layer ranges from 2 to 40 {\AA} with 2 {\AA} steps. We did not observe usual optic and acoustic modes; instead we had two broad overlapped peaks for the films ranged from 6 {\AA} to 40 {\AA}. One interesting result was the high anisotropic resonance field values for these films. Exchange coupling between ferromagnetic layers causes shift on resonance field values but these shifts in our samples were much larger than expected. This large anisotropic behavior is not clear at the moment. Our theoretical model was not able to determine a value for the exchange coupling parameter. One reason can be the close thickness values for Co sublayers. The other reason can be the Ti non-magnetic layer. If titanium did not grow layer by layer on cobalt, the cobalt ferromagnetic layers may behave as a single layer. As a result one cannot observe exchange interaction between ferromagnetic layers through non-magnetic spacer.Comment: 6 pages, 5 figure

Velocity Effect On Inflationary Growth of Turkey: Evidence From Co-integration Analysis and Granger's Causality Test

The Turkish economy has experienced high and persistent inflation rates in the last two decades. This inflation has persisted despite many unsuccessful stabilization policies, which have caused volatility in macro-economic indicators. The main aim of this paper is to analyze the impact of velocity on inflationary trend in Turkey over the period between 1996 and 2001. We assumed that there is a direct relationship between the two factors. However, velocity is not the major cause of inflation. The integration and co-integration tests have been adopted on monthly time series data to test the validity of the model by adding some control variables. Results show that velocity has a weak and negative effect on the inflationary growth of Turkey during this period. The effects of other control variables on inflation growth have also been tested. Some aspects of this linear relationship have been obtained by Granger’s Causality Test.Velocity, Co-Integration Tests, Error Correction Mechanism, Granger’s Test