W and Z production in the forward region at LHCb

Measurements of electroweak boson production in pp collisions at $\sqrt{s} = 7$ TeV are presented using the decays $W \rightarrow \mu\nu$, $Z \rightarrow \mu\mu$ and $Z \rightarrow \tau\tau$ recorded using the LHCb detector at the LHC. For muonic $W$ and $Z$ decays, the data sample corresponds to an integrated luminosity of 37.1 $\pm$ 1.3 pb$^{-1}$. Here the $W$ and $Z$ bosons are reconstructed from muons with transverse momenta, $p_{T}$, above 20 GeV and pseudorapidity, $\eta$, between 2 and 4.5, and, in the case of the $Z$, a dimuon invariant mass $M_{Z}$ between 60 GeV and 120 GeV. For $Z$ decays to tau lepton final states, 247 pb$^{-1}$ of data has been used. Here one tau is identified through its decay to a muon and neutrinos; the other through its decay to an electron or muon and neutrinos. The cross-sections are measured to be: $\sigma(W^{+}\rightarrow\mu^{+}\nu) =$ 808 $\pm$ 7 $\pm$ 28 $\pm$ 28 pb; $\sigma(W^{+}\rightarrow\mu^{+}\nu) =$ 634 $\pm$ 7 $\pm$ 21 $\pm$ 22 pb; $\sigma(Z\rightarrow\mu\mu) =$ 74.9 $\pm$ 1.6 $\pm$ 3.8 $\pm$ 2.6 pb; $\sigma(Z\rightarrow\tau\tau) =$ 82 $\pm$ 8 $\pm$ 7 $\pm$ 4 pb. Here the first error is statistical, the second is systematic and the third is due to the luminosity determination. For muonic final states, differential measurements, cross-section ratios and the $W$ charge asymmetry are also measured in the same kinematic region. The ratio of the $Z\rightarrow\tau\tau$ and $Z\rightarrow\mu\mu$ cross-sections has been measured to be 1.09 $\pm$ 0.17, consistent with lepton universality. Theoretical predictions, calculated at next-to-next-to-leading order (NNLO) in QCD using recent parton distribution functions, are found to be in agreement with the measurements

T-Branes and Geometry

T-branes are a non-abelian generalization of intersecting branes in which the matrix of normal deformations is nilpotent along some subspace. In this paper we study the geometric remnant of this open string data for six-dimensional F-theory vacua. We show that in the dual M-theory / IIA compactification on a smooth Calabi-Yau threefold X, the geometric remnant of T-brane data translates to periods of the three-form potential valued in the intermediate Jacobian of X. Starting from a smoothing of a singular Calabi-Yau, we show how to track this data in singular limits using the theory of limiting mixed Hodge structures, which in turn directly points to an emergent Hitchin-like system coupled to defects. We argue that the physical data of an F-theory compactification on a singular threefold involves specifying both a geometry as well as the remnant of three-form potential moduli and flux which is localized on the discriminant. We give examples of T-branes in compact F-theory models with heterotic duals, and comment on the extension of our results to four-dimensional vacua.Comment: v2: 80 pages, 2 figures, clarifications and references added, typos correcte

Somalia and the Pirates. ESF Working Paper No. 33, 18 December 2009

Piracy is defined by The Hague Centre for Strategic Studies as an "act of boarding or attempting to board any ship with the apparent intent to commit theft or any other crime and with the apparent intent or capability to use force in furtherance of that act." And it is estimated that from 1995 to 2009, around 730 persons were killed or are presumed dead, approximately 3,850 seafarers were held hostage, around 230 were kidnapped and ransomed, nearly 800 were seriously injured and hundreds more were threatened with guns and knives. (See paper by Rob de Wijk). In November 2009, CEPS held a European Security Forum seminar, in collaboration with the Institute for Strategic Studies, the Centre for the Democratic Control of Armed Forces and the Geneva Centre for Security Policy, to focus on the issue of Somalia and the Pirates, chaired by Francois Heisbourg. Four eminent specialists in this field: David Anderson, Rob de Wijk, Steven Haines and Jonathon Stevenson looked at the links with Somalia, and the historical, legal, political and security dimensions of the troubling success of piracy in today’s world. Their conclusions and recommendations for future action are brought together in this ESF 33 Working Paper

Evolution of antigen binding receptors

This review addresses issues related to the evolution of the complex multigene families of antigen binding receptors that function in adaptive immunity. Advances in molecular genetic technology now permit the study of immunoglobulin (Ig) and T cell receptor (TCR) genes in many species that are not commonly studied yet represent critical branch points in vertebrate phylogeny. Both Ig and TCR genes have been defined in most of the major lineages of jawed vertebrates, including the cartilaginous fishes, which represent the most phylogenetically divergent jawed vertebrate group relative to the mammals. Ig genes in cartilaginous fish are encoded by multiple individual loci that each contain rearranging segmental elements and constant regions. In some loci, segmental elements are joined in the germline, i.e. they do not undergo genetic rearrangement. Other major differences in Ig gene organization and the mechanisms of somatic diversification have occurred throughout vertebrate evolution. However, relating these changes to adaptive immune function in lower vertebrates is challenging. TCR genes exhibit greater sequence diversity in individual segmental elements than is found in Ig genes but have undergone fewer changes in gene organization, isotype diversity, and mechanisms of diversification. As of yet, homologous forms of antigen binding receptors have not been identified in jawless vertebrates; however, acquisition of large amounts of structural data for the antigen binding receptors that are found in a variety of jawed vertebrates has defined shared characteristics that provide unique insight into the distant origins of the rearranging gene systems and their relationships to both adaptive and innate recognition processes

Stereoelectronic effects on the binding of neutral Lewis bases to CdSe nanocrystals

Using P-31 nuclear magnetic resonance (NMR) spectroscopy, we monitor the competition between tri-nbutylphosphine (Bu3P) and various amine and phosphine ligands for the surface of chloride terminated CdSe nanocrystals. Distinct P-31 NMR signals for free and bound phosphine ligands allow the surface ligand coverage to be measured in phosphine solution. Ligands with a small steric profile achieve higher surface coverages (Bu3P = 0.5 nm(-2), Me2P-n-octyl = 2.0 nm(-2), NH2Bu = >3 nm(-2)) and have greater relative binding affinity for the nanocrystal (binding affinity: Me3P > Me2P -n-octyl similar to Me2P -n-octadecyl > Et3P > Bu3P). Among phosphines, only Bu 3 P and Me2P-n-octyl support a colloidal dispersion, allowing a relative surface binding affinity (K-rel) to be estimated in that case (K-rel = 3.1). The affinity of the amine ligands is measured by the extent to which they displace Bu3P from the nanocrystals (K-rel: H2NBu similar to N-n-butylimidazole > 4-ethylpyridine > Bu3P similar to HNBu2 > Me2NBu > Bu3N). The affinity for the CdSe surface is greatest among soft, basic donors and depends on the number of each ligand that bind. Sterically unencumbered ligands such as imidazole, pyridine, and n-alkylamines can therefore outcompete stronger donors such as alkylphosphines. The influence of repulsive interactions between ligands on the binding affinity is a consequence of the high atom density of binary semiconductor surfaces. The observed behavior is distinct from the self-assembly of straight-chain surfactants on gold and silver where the ligands are commensurate with the underlying lattice and attractive interactions between aliphatic chains strengthen the binding

Student Reliance on Simulations: The Extent That Engineering Students Rely on the Outcomes of Their Simulations

The purpose of this research was to investigate the factors that contributed to engineering education students’ reliance on technology while learning new concepts. The researcher hypothesized that students would give reliance to their technology, even in the face of evidence that the technology was not working as intended. This research used a mixed-methods approach to answer the research questions. Three questions guided the research: (1) How are the participant’s level of automation complacency and the correctness of the simulation that participant is using related?; (2) How is automation bias related to a participant’s ability to recognize errors in a simulation?; and (3) What factors explain the automation bias and automation complacency that the participants are experiencing? The third research question had two subquestions: (a) What factors explain the correlation between a participant’s level of automation complacency and the correctness of the simulation that participant is using?; and (b) What factors explain the impact that automation bias has on a participant’s ability to recognize errors in that simulation? This study was based on the Theory of Technology Dominance, which states that people are more likely to rely on their technology the less experience they have with the task, the higher the complexity of the task, the lower the familiarity with the technology, and the further the technology is from the skillsets needed to solve the problem. This framework is built on the automation bias and automation complacency given by an individual towards technology. Automation bias is an overreliance on automation results despite contradictory information being produced by humans, while automation complacency is the acceptance of results from automation because of an unjustifiable assumption that the automation is working satisfactorily. To ensure that the study could gather the information necessary, the mixed-study utilized deception techniques to divide participants into separate groupings. Four groupings were created, with some participants being given a properly functioning simulation with others being given a faulty simulation. Half of each grouping were informed that the simulation may have errors, while others were not. All participants who completed the study were debriefed about the real purpose of the study, but only after information had been gathered for analysis. The simulation given to all participants was designed to help students learn and practice the Method of Joints. Students participating in the statics courses taught in the College of Engineering courses at Utah State University were invited to participate in the program over Spring and Fall semesters of 2022. Sixty-nine participants began the study, but only thirty-four remained in the study through to completion. Each participant took a pre-questionnaire, worked with a provided simulation that was either correct or incorrect, were possibly informed of potential errors in the simulation, and took a post-questionnaire. A few participants were invited to participate in an interview. The findings of this study revealed that students often have high levels of automation bias and automation complacency. Participants changed their answers from wrong answers to right answers more often when using correct simulations and from right answer to wrong answers more often when using faulty simulations. The accuracy of each participant’s responses was also higher for those with correct simulations than faulty simulations. And most participants expressed that they checked their work and changed their answers when the simulation asked them to. These findings were confirmed through the use of the post-questionnaire results and in interview analysis between the groups

Conversion of PA 611 Public Administration Theory and Practice

This project focused on converting PA 611 Public Administration Theory and Practice into an online course suitable for certification by the California State University Quality Learning and Teaching (QLT) program. http://courseredesign.csuprojects.org/wp/qualityassurance/qlt/ Following three workshops and one on one work with Instructional Designer Gary Johnson, PA 611 was converted utilizing the course alignment and accessibility requirements of QLT. Each module is structured to have learning goals, readings, videos and assignments aligned with the Course learning outcomes