714 research outputs found

    Vegetative regeneration in Aspen: Ecology and Management in the Western United States

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    A Guidebook: navigating custody and access negotiation

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    guidelines for family negotiation: what to do in the interest of minors after a family breakup

    pi-Conjugation and conformation in a semiconducting polymer: small angle x-ray scattering study

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    Small angle X-ray scattering (SAXS) in poly[2-methoxy-5-(2-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV) solution has shown the important role of pi-electron conjugation in controlling the chain conformation and assembly. By increasing the extent of conjugation from 30 to 100 %, the persistence length (l_p) increases from 20 to 66 Angstrom. Moreover, a pronounced second peak in the pair distribution function has been observed in fully conjugated chain, at larger length scales. This feature indicates that the chain segments tend to self-assemble as the conjugation along the chain increases. Xylene enhances the rigidity of PPV backbone to yield extended structures, while tetrahydrofuran solvates the side groups to form compact coils in which the l_p is much shorter.Comment: accepted (J. Phy. Cond. Mat.

    Linkage analysis of depression spectrum disease

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    As part of a study of the possible subgroups of unipolar affective disease, 27 families were ascertained as depression spectrum disease (DSD) families. The purpose of this study was an investigation of the linkage relationships between DSD and 30 genetic markers using the robust sib-pair and lod-score methods. Using the sib-pair methods, evidence for linkage was found with orosomucoid (ORM) on chromosome 9q (p = 0.006), regardless of whether only individuals with unipolar depression, alcoholism, or antisocial personality were considered to be affected, or whether individuals with any psychiatric disorder were considered to be affected. Weak evidence of linkage with ORM was corroborated using lod-score methods when a narrow definition of depression spectrum disease was used, although stronger evidence of linkage was found with ORM when any psychiatric disorder was considered to be affected. The maximum lod-score for ORM was 1.68 at a male recombination fraction of 0.23 and a female recombination fraction of 0.01.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27905/1/0000325.pd

    Structure, Photophysics and the Order-Disorder Transition to the Beta Phase in Poly(9,9-(di -n,n-octyl)fluorene)

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    X-ray diffraction, UV-vis absorption and photoluminescence (PL) spectroscopy have been used to study the well-known order-disorder transition (ODT) to the beta phase in poly(9,9-(di n,n-octyl)fluorene)) (PF8) thin film samples through combination of time-dependent and temperature-dependent measurements. The ODT is well described by a simple Avrami picture of one-dimensional nucleation and growth but crystallization, on cooling, proceeds only after molecular-level conformational relaxation to the so called beta phase. Rapid thermal quenching is employed for PF8 studies of pure alpha phase samples while extended low-temperature annealing is used for improved beta phase formation. Low temperature PL studies reveal sharp Franck-Condon type emission bands and, in the beta phase, two distinguishable vibronic sub-bands with energies of approximately 199 and 158 meV at 25 K. This improved molecular level structural order leads to a more complete analysis of the higher-order vibronic bands. A net Huang-Rhys coupling parameter of just under 0.7 is typically observed but the relative contributions by the two distinguishable vibronic sub-bands exhibit an anomalous temperature dependence. The PL studies also identify strongly correlated behavior between the relative beta phase 0-0 PL peak position and peak width. This relationship is modeled under the assumption that emission represents excitons in thermodynamic equilibrium from states at the bottom of a quasi-one-dimensional exciton band. The crystalline phase, as observed in annealed thin-film samples, has scattering peaks which are incompatible with a simple hexagonal packing of the PF8 chains.Comment: Submitted to PRB, 12 files; 1 tex, 1 bbl, 10 eps figure

    Cephalosporin-resistant Escherichia coli among Summer Camp Attendees with Salmonellosis

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    Investigation of an acute gastroenteritis outbreak involving >100 persons at a summer camp in Girona, Spain, in June 2002 led to the detection of Salmonella and extended-spectrum cephalosporin-resistant Escherichia coli (ESCREC). Stool cultures were performed for 22 symptomatic campers, three asymptomatic food handlers, and 10 healthy household members. Of the 22 campers, 19 had Salmonella enterica, 9 had an ESCREC strain carrying an extended-spectrum β-lactamase, and 2 had a second ESCREC strain carrying a plasmidic cephamycinase. Related ESCREC were detected in two (salmonella-negative) asymptomatic food handlers and in none of the healthy household members. Fecal ESCREC and its β-lactamases and plasmids were extensively characterized. Three of the five ESCREC clones were recovered from multiple hosts. The apparent dissemination of ESCREC suggests a food or water vehicle. The observed distribution of resistance plasmids and β-lactamase genes in several clones indicates a high degree of horizontal transfer. Heightened vigilance and increased efforts must be made to discover the reservoirs and vehicles for community dissemination of ESCREC
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