Top cross section ratios as a test of lepton universality in charged weak decays in proton-proton collisions at s\sqrt{s} = 7 TeV with the atlas detector

In this thesis partial production cross sections of ${tṫ}$ events are measured in four channels, defined by the final state leptons from the decay of the $W$ bosons and the triggering lepton, using ~5.6 fb$^{-1}$ of data taken with the ATLAS detector at $\sqrt{s}$ = 7 TeV. The di-lepton channel is defined as having one electron and one muon in the final state. The lepton plus tauchannels are defined as having a final state electron or muon and one hadronically decaying tau. Partial cross sections for these channels are estimated, and ratios of partial cross sections, defined with the same triggering lepton, are calculated. The di-lepton events are divided into two non-exclusive channels defined by the presence of a trigger matched lepton. The production cross-sections of $t$\overline{t} events with final states including an electron and a hadronically decaying tau, or an electron and a muon, were measured and used to calculate their ratio $R$$_{er}$ = 0.65$_{-0.10}$$^{+0.12}$($stat.$) ± 0.18($syst.$). The cross section ratio $R$$_{er}$ measured in data is compared to that inferred from the world average $W$ and tau branching fractions, $R$$_{er}$$^{Data}$/$R$$_{er}$$^{PDG}$ = 1.1$_{-0.17}$$^{+0.21}$($stats.$) ± 0.31($syst.$) and is found to be consistent with unity

Introductory programming: a systematic literature review

As computing becomes a mainstream discipline embedded in the school curriculum and acts as an enabler for an increasing range of academic disciplines in higher education, the literature on introductory programming is growing. Although there have been several reviews that focus on specific aspects of introductory programming, there has been no broad overview of the literature exploring recent trends across the breadth of introductory programming. This paper is the report of an ITiCSE working group that conducted a systematic review in order to gain an overview of the introductory programming literature. Partitioning the literature into papers addressing the student, teaching, the curriculum, and assessment, we explore trends, highlight advances in knowledge over the past 15 years, and indicate possible directions for future research

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Top Cross Section Ratios as Test of Lepton Universality in Charged Weak Decays in Proton-Proton Collisions at s+7\sqrt{s}+7 TeV with the ATLAS Detector

In this thesis partial production cross sections of t t events are measured in four channels, dened by the nal state leptons from the decay of the W bosons and the triggering lepton, using 5 : 6 fb -1of data taken with the ATLAS detector at p s = 7 TeV. The di-lepton channel is dened as having one electron and one muon in the nal state. The lepton plus tau channels are dened as having a nal state electron or muon and one hadronically decaying tau. Partial cross sections for these channels are estimated, and ratios of partial cross sections, dened with the same triggering lepton, are calculated. The di-lepton events are divided into two non-exclusive channels dened by the presence of a trigger matched lepton. The production cross-sections of t t events with nal states including an electron and a hadronically decaying tau, or an electron and a muon, were measured and used to calculate their ratio R e = 0 : 65 +0 : 12 -0.10 (stat.) + - 0.18(syst.). The cross section ratio R e measured in data is compared to that inferred from the world average W and tau branching fractions, R Data e = R PDG e = 1 : 1 +0 : 21 -0.17(stat.) +-0.31(syst.) and is found to be consistent with unity

Can management practices provide greenhouse gas abatement in grain farms in New South Wales, Australia?

Greenhouse gas abatement in the agricultural cropping industry can be achieved by employing management practices that sequester soil carbon (C) or minimise nitrous oxide (N2O) emissions from soils. However, C sequestration stimulates N2O emissions, making the net greenhouse-gas abatement potential of management practices difficult to predict. We studied land-management practices that have potential to mitigate greenhouse gas emissions by increasing soil C storage and/or decreasing soil N2O emissions for a diverse range of broadacre grain cropping sites in New South Wales. Carbon sequestration and N2O emissions were simulated with the Agricultural Production Systems Simulator (APSIM) for a baseline crop-management scenario and alternative scenarios representing management practices for greenhouse gas abatement, for 15 rainfed or irrigated sites. The global warming potential of the scenarios was quantified at 25 and 100 years after commencement of the alternative practices. Soil C and N2O emissions were predicted to increase with the use of practices that increased organic matter additions to the soil (e.g. adding a summer crop to the rotation). However, in only a few cases did the increase in soil C storage counter the N2O emissions sufficiently to provide net greenhouse gas abatement. For rainfed sites, inclusion of a summer crop and/or a pasture in the rotation was predicted to provide greenhouse gas abatement after 25 years, whereas after 100 years, only practices that included a summer crop provided abatement for some sites. For irrigated sites after 25 years, practices that reduced N fertiliser rate while retaining stubble were predicted to provide small abatement, and practices that included a summer crop provided abatement for some sites. After 100 years, practices likely to provide abatement included those that reduced N2O emissions, such as reducing N fertiliser rate. These findings suggest that a few management practices are likely to abate greenhouse gas emissions across New South Wales grain production sites and that these practices differ for irrigated and rainfed sites