Diel dissolved oxygen patterns and aquatic life use assessment

This report mentions Waller Creek as one of three streams "listed as "of concern" for DO impairments".Diel dissolved oxygen (DO) data from 318 deployments at 38 stream sites were evaluated for spatial and temporal patterns and compared using TCEQ aquatic life use assessment DO criteria versus benthic macroinvertebrate aquatic life use categories. Diel DO data suggest that Austin streams generally maintain high or excellent aquatic life use potential. TCEQ assessment methods may not be appropriate for identifying aquatic life use impairments in some high quality Austin streams, and may yield impairments based on DO that are not observed in benthic macroinvertebrate data. Additional investigation of low DO in Bull Creek preserve lands is needed.Waller Creek Working Grou

Static-light meson masses from twisted mass lattice QCD

We compute the static-light meson spectrum using two-flavor Wilson twisted mass lattice QCD. We have considered five different values for the light quark mass corresponding to 300 MeV < m_PS < 600 MeV. We have extrapolated our results, to make predictions regarding the spectrum of B and B_s mesons.Comment: 7 pages, 2 figures, talk given at the XXVI International Symposium on Lattice Field Theory, July 14 - 19 2008, Williamsburg, Virginia, US

TIPO, BRAZIL'S 'LIKE': SYNCHRONIC FUNCTIONAL AND PHONETIC ANALYSES OF NOMINAL, GRAMMATICAL, AND DISCOURSE FUNCTIONS

Previous research in Brazilian Portuguese has indicated that the noun tipo 'type,' 'kind' is undergoing grammaticalization (Bittencourt, 1999; Lima-Hernandes, 2005). Review of the literature, however, reveals a limited number of studies that provide an account of its current state in conversational speech. Moreover, research on the grammaticalization of tipo has been mostly limited to the examination of its multifunctionality (Bittencourt, 1999; Laurentino,2016; Lima-Hernandes, 2005), resulting in a gap as to how the processes of grammaticalization may be reflected on its use and production. Using data from the Projeto Sociolingüístico Contemporâneo Brasileiro corpus (Thompson & Onosson, 2016), comprised of sociolinguistic interviews conducted with teenage public-school students in Rio de Janeiro, this dissertation presents the findings of a study that examined the current state of tipo in conversational discourse. An innovative multimethodological approach was employed aiming to address tipo's functional diversity. Distributional, functional, acoustic, and perceptual investigations were conducted with the goal to gain insight into some of the processes tipo is undergoing as it sheds its nominal properties and acquires new grammatical, discourse, and pragmatic functions. Results reveal a functional expansion of tipo, which was found to be performing roles such as a preposition, a conjunction, and a discourse marker among others. More notably, results from a subsequent acoustic analysis reveal consistent differences in pronunciation between nominal and non-nominal forms, suggesting that as tipo expands to perform new functions, speakers are encoding such changes at the segment level. A discrimination task conducted with 98 teenage students also confirmed that speakers are able to discriminate nominal from non-nominal forms, suggesting that other processes beyond durational differences may be playing a role in the grammaticalization of that noun

Effects of drinking-water filtration on Cryptosporidium Seroepidemiology, Scotland

Continuous exposure to low levels of Cryptosporidium oocysts is associated with production of protective antibodies. We investigated prevalence of antibodies against the 27-kDa Cryptosporidium oocyst antigen among blood donors in 2 areas of Scotland supplied by drinking water from different sources with different filtration standards: Glasgow (not filtered) and Dundee (filtered). During 2006–2009, seroprevalence and risk factor data were collected; this period includes 2007, when enhanced filtration was introduced to the Glasgow supply. A serologic response to the 27-kDa antigen was found for ≈75% of donors in the 2 cohorts combined. Mixed regression modeling indicated a 32% step-change reduction in seroprevalence of antibodies against Cryptosporidium among persons in the Glasgow area, which was associated with introduction of enhanced filtration treatment. Removal of Cryptosporidium oocysts from water reduces the risk for waterborne exposure, sporadic infections, and outbreaks. Paradoxically, however, oocyst removal might lower immunity and increase the risk for infection from other sources

A comparative study of density functional and density functional tight binding calculations of defects in graphene

The density functional tight binding approach (DFTB) is well adapted for the study of point and line defects in graphene based systems. After briefly reviewing the use of DFTB in this area, we present a comparative study of defect structures, energies and dynamics between DFTB results obtained using the dftb+ code, and density functional results using the localised Gaussian orbital code, AIMPRO. DFTB accurately reproduces structures and energies for a range of point defect structures such as vacancies and Stone-Wales defects in graphene, as well as various unfunctionalised and hydroxylated graphene sheet edges. Migration barriers for the vacancy and Stone-Wales defect formation barriers are accurately reproduced using a nudged elastic band approach. Finally we explore the potential for dynamic defect simulations using DFTB, taking as an example electron irradiation damage in graphene

High Harmonic Generation in SF6_{6}: Raman-excited Vibrational Quantum Beats

In a recent experiment (N. Wagner et al., PNAS v103, p13279) on SF$_{6}$, a high-harmonic generating laser pulse is preceded by a pump pulse which stimulates Raman-active modes in the molecule. Varying the time delay between the two pulses modulates high harmonic intensity, with frequencies equal to the vibration frequencies of the Raman-active modes. We propose an explanation of this modulation as a quantum interference between competing pathways that occur via adjacent vibrational states of the molecule. The Raman and high harmonic processes act as beamsplitters, producing vibrational quantum beats among the Raman-active vibrational modes that are excited by the first pulse. We introduce a rigorous treatment of the electron-ion recombination process and the effect of the ionic Coulomb field in the electron propagation outside the molecule, improving over the widely-used three-step model.Comment: submitted to PR