Surface Studies of C60 on Ferromagnetic Ni/Cu(100) and Co/Ru(OOOl) Thin Film Systems

This dissertation determined how the electronic and atomic structure of Ni/Cu(100) and Co/Ru(0001) thin films affect C6O-metal bonding and local magnetic properties at the surface. In-situ spin-averaged and spin-polarized scanning tunneling microscopy and spectroscopy techniques were used in this study. Homoepitaxial growth studies of Ni(100) and Co(0001) films investigated the influence of C60 on film growth. On 7.6 ML Ni films, C60 showed no obvious effect on the continued crystalline growth of Ni. The low mobility of C60 on the Ni surface and high Ni diffusion barrier limited the occurrence of Ni-C60 collisions during growth. On 1.84 ML Co films, crystalline growth with moire reconstructions continued with CGO present at the surface. However, Co islands were observed only nucleating and growing from step edges and around C60 suggesting the Co-C6O bond is stronger than the Co-Co bond on Co terraces. C60 mobility was also observed to vary across the Co film surface due to local variations in film reconstruction and dislocation networks. The results show that the nature of the C60-metallic bond at the surface can effect film growth and morphology. Scanning tunneling spectroscopy (STS) studies suggest that the spin-averaged and spinpolarized Co(0001) electronic structure is influenced by a number of factors: (i) sequential layer stacking (fcc/hcp), (ii) strain-induced reconstruction (moire), (iii) Co film thickness, and (iv) dislocations and defects at the surface. Spin-polarized STS measurements resolved spectral contributions from Co layer stacking and opposite perpendicular magnetic spin-orientations. The magnetic domain regions identified were fcctt/fcet..J, and hcptt/hcpt..J, stacked domains, respectively. No evidence of an in-plane magnetic spin-orientation or spin re-orientation transition was observed at the Co surface; however magnetic domain walls showed evidence of pinning at dislocation lines. Spin-polarized STM/STS measurements did not reveal any affect of C60 on the local magnetic properties of Co. However, an internal structure of C60 molecules adsorbed on the Co(0001) film surface was observed, corresponding to a 3-fold (symmetry) molecular-orientation; and in the near-region where CGO clusters were adsorbed, Co surface state peaks were observed to be absent, suggesting the local electronic structure of Co is perturbed by the presence of C60

Review of the United States Environmental Protection Agency Superfund Technical Assistance Grant Program

The EPA Technical Assistance Grant Program has been around for several years, but there are not many examples of its use in the Pacific Northwest from which citizens can learn from when considering applying for a Technical Assistance Grant. The EPA program is designed to provide citizens with technical assistance in understanding the issues related to a Superfund site (or proposed Superfund site) in their community. This report provides an overview of the Technical Assistance Grant Program with information on applying for the grant, selecting a Technical Advisor and managing the grant. Additionally two case studies are reviewed in order to provide some examples of the process and provide a better understanding of the steps involved for new communities interested in utilizing this EPA program. By examining both the TAG process and some examples of its implementation, interested citizens will be better prepared for the grant process, the efforts involved, and the benefits of the grant program

Do toddlers prefer the primary caregiver or the parent with whom they feel more secure? The role of toddler emotion

This study tested Bowlby and Ainsworth’s hypothesis that a hierarchy of caregivers exists whereby infants prefer one caregiver over another when distressed. We examined parent gender (mother vs. father), primary caregiver status (defined as the parent who spent most time with the infant and performed most of the caregiving tasks), and role of toddlers’ history of attachment security with each parent, as predictors of toddlers’ preference for a particular caregiver when the toddlers are distressed and when they are content. Infants’ attachment security with each parent was assessed at 12–15 months. At 24 months, mother–child and father–child interactions were observed in triadic (mother, father, toddler) home interactions. When distressed, regardless of the security of their attachment to each parent, toddlers more often interacted with the primary caregiver. When content, toddlers did not show this preference. As expected, toddlers’ recovery from distress was predicted by their security of attachment with the parent whom they approached when distressed

Strange homelands: encountering the migrant on the contemporary Greek stage

This article examines three examples from recent Greek theatre which stage experiences of migrants and refugees against the backdrop of Greece’s growing internationalism and multiculturalism. In allowing migrants to author their own narratives of border-crossing and encountering their new “homeland”, those theatrical endeavours, I argue, attempt to break the monologism of Greek theatre and monolithic understandings of national identity thus opening up spaces for encountering diverse voices. In acknowledging the risks and tensions underpinning the migrant’s presence on stage, the article also applies pressure to questions of encounter, authenticity, representation and self-expression of migratory subjects and interrogates some ways in which they navigate their precarious space of belonging and author themselves in the context of contemporary Greek theatre

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

Measurement of the top quark forward-backward production asymmetry and the anomalous chromoelectric and chromomagnetic moments in pp collisions at √s = 13 TeV

Abstract The parton-level top quark (t) forward-backward asymmetry and the anomalous chromoelectric (d̂ t) and chromomagnetic (μ̂ t) moments have been measured using LHC pp collisions at a center-of-mass energy of 13 TeV, collected in the CMS detector in a data sample corresponding to an integrated luminosity of 35.9 fb−1. The linearized variable AFB(1) is used to approximate the asymmetry. Candidate t t ¯ events decaying to a muon or electron and jets in final states with low and high Lorentz boosts are selected and reconstructed using a fit of the kinematic distributions of the decay products to those expected for t t ¯ final states. The values found for the parameters are AFB(1)=0.048−0.087+0.095(stat)−0.029+0.020(syst),μ̂t=−0.024−0.009+0.013(stat)−0.011+0.016(syst), and a limit is placed on the magnitude of | d̂ t| < 0.03 at 95% confidence level. [Figure not available: see fulltext.

MUSiC : a model-unspecific search for new physics in proton-proton collisions at root s=13TeV

Results of the Model Unspecific Search in CMS (MUSiC), using proton-proton collision data recorded at the LHC at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9 fb(-1), are presented. The MUSiC analysis searches for anomalies that could be signatures of physics beyond the standard model. The analysis is based on the comparison of observed data with the standard model prediction, as determined from simulation, in several hundred final states and multiple kinematic distributions. Events containing at least one electron or muon are classified based on their final state topology, and an automated search algorithm surveys the observed data for deviations from the prediction. The sensitivity of the search is validated using multiple methods. No significant deviations from the predictions have been observed. For a wide range of final state topologies, agreement is found between the data and the standard model simulation. This analysis complements dedicated search analyses by significantly expanding the range of final states covered using a model independent approach with the largest data set to date to probe phase space regions beyond the reach of previous general searches.Peer reviewe

Search for new particles in events with energetic jets and large missing transverse momentum in proton-proton collisions at root s=13 TeV

A search is presented for new particles produced at the LHC in proton-proton collisions at root s = 13 TeV, using events with energetic jets and large missing transverse momentum. The analysis is based on a data sample corresponding to an integrated luminosity of 101 fb(-1), collected in 2017-2018 with the CMS detector. Machine learning techniques are used to define separate categories for events with narrow jets from initial-state radiation and events with large-radius jets consistent with a hadronic decay of a W or Z boson. A statistical combination is made with an earlier search based on a data sample of 36 fb(-1), collected in 2016. No significant excess of events is observed with respect to the standard model background expectation determined from control samples in data. The results are interpreted in terms of limits on the branching fraction of an invisible decay of the Higgs boson, as well as constraints on simplified models of dark matter, on first-generation scalar leptoquarks decaying to quarks and neutrinos, and on models with large extra dimensions. Several of the new limits, specifically for spin-1 dark matter mediators, pseudoscalar mediators, colored mediators, and leptoquarks, are the most restrictive to date.Peer reviewe

Measurement of prompt open-charm production cross sections in proton-proton collisions at root s=13 TeV

The production cross sections for prompt open-charm mesons in proton-proton collisions at a center-of-mass energy of 13TeV are reported. The measurement is performed using a data sample collected by the CMS experiment corresponding to an integrated luminosity of 29 nb(-1). The differential production cross sections of the D*(+/-), D-+/-, and D-0 ((D) over bar (0)) mesons are presented in ranges of transverse momentum and pseudorapidity 4 < p(T) < 100 GeV and vertical bar eta vertical bar < 2.1, respectively. The results are compared to several theoretical calculations and to previous measurements.Peer reviewe

Combined searches for the production of supersymmetric top quark partners in proton-proton collisions at root s=13 TeV

A combination of searches for top squark pair production using proton-proton collision data at a center-of-mass energy of 13 TeV at the CERN LHC, corresponding to an integrated luminosity of 137 fb(-1) collected by the CMS experiment, is presented. Signatures with at least 2 jets and large missing transverse momentum are categorized into events with 0, 1, or 2 leptons. New results for regions of parameter space where the kinematical properties of top squark pair production and top quark pair production are very similar are presented. Depending on themodel, the combined result excludes a top squarkmass up to 1325 GeV for amassless neutralino, and a neutralinomass up to 700 GeV for a top squarkmass of 1150 GeV. Top squarks with masses from 145 to 295 GeV, for neutralino masses from 0 to 100 GeV, with a mass difference between the top squark and the neutralino in a window of 30 GeV around the mass of the top quark, are excluded for the first time with CMS data. The results of theses searches are also interpreted in an alternative signal model of dark matter production via a spin-0 mediator in association with a top quark pair. Upper limits are set on the cross section for mediator particle masses of up to 420 GeV