2,124 research outputs found

    A theoretical simulation of the resonant Raman spectroscopy of the H2Oâ‹ŻCl2 and H2Oâ‹ŻBr2 halogen-bonded complexes

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    The resonant Raman spectra of the H2O⋯Cl2 and H2O⋯Br2 halogen-bonded complexes have been studied in the framework of a 2-dimensional model previously used in the simulation of their UV-visible absorption spectra using time-dependent techniques. In addition to the vibrational progression along the dihalogen mode, a progression is observed along the intermolecular mode and its combination with the intramolecular one. The relative intensity of the inter to intramolecular vibrational progressions is about 15% for H2O⋯Cl2 and 33% for H2O⋯Br2. These results make resonant Raman spectra a potential tool for detecting the presence of halogen bonded complexes in condensed phase media such as clathrates and ice.Fil: Franklin Mergarejo, Ricardo. Université Paris Sud; Francia. Centre National de la Recherche Scientifique; Francia. InSTEC; Cuba. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Rubayo Soneira, Jesús. InSTEC; CubaFil: Halberstadt, Nadine. Université Paris Sud; Francia. Centre National de la Recherche Scientifique; FranciaFil: Janda, Kenneth C.. University of California at Irvine; Estados UnidosFil: Apkarian, V. Ara. University of California at Irvine; Estados Unido

    Generalized boundary strata classes

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    We describe a generalization of the usual boundary strata classes in the Chow ring of M‾g,n\overline{\mathcal{M}}_{g,n}. The generalized boundary strata classes additively span a subring of the tautological ring. We describe a multiplication law satisfied by these classes and check that every double ramification cycle lies in this subring.Comment: For the Proceedings of the 2017 Abel Symposium, 10 page

    Microbial characterization and biodegradation potential in novel filtration systems designed to remove sulfolane from potable water

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    Thesis (M.S.) University of Alaska Fairbanks, 2016Sulfolane is an emerging contaminant used as a solvent in natural gas refineries. In response to a sulfolane spill in North Pole, Alaska, that contaminated portions of the community water supply, a novel water filtration system utilizing granular activated carbon (GAC) was developed and installed in households affected by the contaminated water. While GAC is capable of adsorbing sulfolane, it is unclear whether microorganisms contribute to sulfolane removal in the filtration systems. We characterized the microbial community found within the filtration systems using quantitative PCR (qPCR) and 16S rRNA gene sequencing and assessed the aerobic sulfolane biodegradation potential of the microbial community adhered to the GAC by measuring sulfolane loss over time in incubations using gas chromatography mass spectrometry (GC-MS). Bacterial and archaeal DNA was detected in influent and effluent water as well as throughout the point-of-entry (POE) systems, but on average, influent water contained over 99% more bacterial and archaeal DNA compared to effluent samples. In addition, a difference in microbial biomass was also observed based on the location of the GAC in the filtering system. GAC located distally to the inlet contained more biomass than the GAC that was more proximal within a canister. This difference may be due to increased flow rates at the inlet preventing microbes from adhering to the GAC. The phylum Proteobacteria dominated the bacterial community on the GAC, with over 60% of the sequences assigned to this phylum. No significant biodegradation was observed when GAC used in a POE system was incubated aerobically with sulfolane for 10 weeks. This study provides the first known description of the microbial community in filtration systems used to remove sulfolane. The findings suggest that aerobic microbial processes do not contribute to sulfolane removal in these systems. Instead, processes such as sorption or UV-induced transformations may be responsible for sulfolane removal. Future research on the potential for anaerobic biodegradation and the production and release of sulfolane breakdown products by anaerobic or photooxidative processes would be warranted.1. Introduction -- 2. Methods -- 2.1 Granular activated carbon sampling -- 2.2 Water sample collection -- 2.3 DNA extraction and analyses -- 2.3.1 GAC DNA extraction -- 2.3.2 POE water sample DNA extraction -- 2.3.3 PCR and qPCR -- 2.3.4 Bacterial community analysis -- 2.3.4 Bacterial community analysis -- 2.5 Gas chromatography-mass spectrometry (GC-MS) -- 2.6 Nucleotide sequence accession numbers -- 3. Results -- 3.1 Microbial DNA detection and quantification -- 3.2 Bacterial community analyses -- 3.3 Sulfolane biodegradation potential -- 4. Discussion -- 5. References

    Infrared photochemistry of ethylene clusters

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    Infrared irradiation of ethylene clusters formed in supersonic molecular beams, using a low power cw CO2 laser, results in the photodissociation of a large fraction of the van der Waals molecules. Under such conditions, infrared absorption intensity exhibits first-order power dependence and is readily detected as loss in molecular beam intensity. Intramolecular energy transfer rates, determined by measuring spectral linewidths, are shown to vary with the vibrational mode initially excited. Ethylene clusters containing one quantum of vibrational energy corresponding to the nun7 fundamental in the monomer (949 cm^–1) have a vibrationally predissociative lifetime of 0.33 psec. In comparison, the relaxation rate of ethylene-d4 clusters with one quantum of excitation corresponding to the nu12 (1078 cm^–1) mode of C2D4 is 0.7 psec

    Seeking the Pressure Points: Catalysing Low Carbon Changes from the Middle-Out in Offices and Schools

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    Non-domestic buildings are frequently characterised as resistant to top-down low-carbon and energy-efficiency policy. Complex relationships amongst building stakeholders are often blamed. “Middle actors”—professionals situated between policymakers and building users—can use their agency and capacity to facilitate energy and carbon decision-making from the “middle-out”. We use semi-structured interviews with expert middle actors working with schools and commercial offices, firstly, to explore their experience of energy and low-carbon decision-making in buildings and, secondly, to reflect on the evolution of middle actors’ role within it. Our exploratory findings suggest that a situated sensitivity to organisational “pressure points” can enhance middle actors’ agency and capacity to catalyse change. We find shifts in the ecology of the “middle”, as the UK’s Net Zero and Environmental, Social and Governance (ESG) agendas pull in new middle actors (such as the financial community) and issues (such as wellbeing and social value) to non-domestic buildings. These issues may work in reinforcing ways with organisational pressure points. Policy should capitalise on this impetus by looking beyond the physicality of individual buildings and engage with middle actors at a systemic level. This could create greater synergies with organisational concerns and strategies of building stakeholders

    Basel II, External Ratings and Adverse Selection

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    This paper will describe and analyse the development of Basel II Capital Accord and will focus on the use of external ratings in the Standardized Approach in Basel II. Furthermore it will examine the problem of adverse selection which appears in Basel II as a result from the proposal for the use of external ratings in determining the risk weights in the standardized approach. The paper will also attempt to find possible solutions to the adverse selection problem by discussing two similar models, and derive implications from them.Basel II, external ratings, adverse selection, rating agencies, standardized approach

    The shape of jamming arches in two-dimensional deposits of granular materials

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    We present experimental results on the shape of arches that block the outlet of a two dimensional silo. For a range of outlet sizes, we measure some properties of the arches such as the number of particles involved, the span, the aspect ratio, and the angles between mutually stabilizing particles. These measurements shed light on the role of frictional tangential forces in arching. In addition, we find that arches tend to adopt an aspect ratio (the quotient between height and half the span) close to one, suggesting an isotropic load. The comparison of the experimental results with data from numerical models of the arches formed in the bulk of a granular column reveals the similarities of both, as well as some limitations in the few existing models.Comment: 8 pages; submitted to Physical Review

    Consumer acceptance of patient-performed mobile teledermoscopy for the early detection of melanoma

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    Background Mobile teledermoscopy allows consumers to send images of skin lesions to a teledermatologist for remote diagnosis. Currently, technology acceptance of mobile teledermoscopy by people at high risk of melanoma is unknown. Objectives We aimed to determine the acceptance of mobile teledermoscopy by consumers based on perceived usefulness, ease of use, compatibility, attitude/intention, subjective norms, facilitators and trust before use. Consumer satisfaction was explored after use

    Does quality of life among breast cancer survivors one year after diagnosis differ depending on urban and non-urban residence? A comparative study

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    Background: This study examined the quality of life (QOL), measured by the Functional Assessment of Cancer Therapy (FACT) questionnaire, among urban (n=277) and non-urban (n=323) breast cancer survivors and women from the general population (n=1140) in Queensland, Australia. ----------\ud Methods: Population-based samples of breast cancer survivors aged <75 years who were 12 months post-diagnosis and similarly-aged women from the general population were recruited between 2002 and 2007. ----------\ud Results: Age-adjusted QOL among urban and non-urban breast cancer survivors was similar, although QOL related to breast cancer concerns was the weakest domain and was lower among non-urban survivors than their urban counterparts (36.8 versus 40.4, P<0.01). Irrespective of residence, breast cancer survivors, on average, reported comparable scores on most QOL scales as their general population peers, although physical well-being was significantly lower among non-urban survivors (versus the general population, P<0.01). Overall, around 20%-33% of survivors experienced lower QOL than peers without the disease. The odds of reporting QOL below normative levels were increased more than two-fold for those who experienced complications following surgery, reported upper-body problems, had higher perceived stress levels and/or a poor perception of handling stress (P<0.01 for all). ----------\ud Conclusions: Results can be used to identify subgroups of women at risk of low QOL and to inform components of tailored recovery interventions to optimize QOL for these women following cancer treatment
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