7,520 research outputs found

    Closed Quasi-Fuchsian Surfaces In Hyperbolic Knot Complements

    Full text link
    We show that every hyperbolic knot complement contains a closed quasi-Fuchsian surface.Comment: 69 pages, 27 figures. Made small changes suggested by refere

    Food Environment, Built Environment, and Women\u27s BMI: Evidence from Erie County, New York

    Get PDF
    The authors present the results of a neighborhood-scaled exploratory study that tests the association of the food environment and the built environment with women’s body mass index (BMI) in Erie County, New York. The proximity of women’s homes to a supermarket relative to a convenience store is associated with lower BMI. A diverse land use mix in a neighborhood is positively associated with women’s BMI, especially when restaurants dominate nonresidential land use. The article offers suggestions for how food environments may be improved using planning strategies

    Systematic comparison of monoclonal versus polyclonal antibodies for mapping histone modifications by ChIP-seq.

    Get PDF
    BackgroundThe robustness of ChIP-seq datasets is highly dependent upon the antibodies used. Currently, polyclonal antibodies are the standard despite several limitations: They are non-renewable, vary in performance between lots and need to be validated with each new lot. In contrast, monoclonal antibody lots are renewable and provide consistent performance. To increase ChIP-seq standardization, we investigated whether monoclonal antibodies could replace polyclonal antibodies. We compared monoclonal antibodies that target five key histone modifications (H3K4me1, H3K4me3, H3K9me3, H3K27ac and H3K27me3) to their polyclonal counterparts in both human and mouse cells.ResultsOverall performance was highly similar for four monoclonal/polyclonal pairs, including when we used two distinct lots of the same monoclonal antibody. In contrast, the binding patterns for H3K27ac differed substantially between polyclonal and monoclonal antibodies. However, this was most likely due to the distinct immunogen used rather than the clonality of the antibody.ConclusionsAltogether, we found that monoclonal antibodies as a class perform equivalently to polyclonal antibodies for the detection of histone post-translational modifications in both human and mouse. Accordingly, we recommend the use of monoclonal antibodies in ChIP-seq experiments

    Production and temperature sensitivity of long chain alkenones in the cultured haptophyte Pseudoisochrysis paradoxa

    Get PDF
    The alkenone unsaturation index (U<sub>37</sub><sup>K</sup> or U<sub>37</sub><sup>K′</sup>) serves as a critical tool for reconstructing temperature in marine environments. Lacustrine haptophyte algae are genetically distinct from their ubiquitous and well studied marine counterparts, and the unknown species-specific genetic imprints on long chain alkenone production by lacustrine species have hindered the widespread application of the U37<sup>K</sup> temperature proxy to lake sediment records. The haptophyte Pseudoisochrysis paradoxa produces alkenones but its U37<sup>K</sup> calibration has never been determined. It has an alkenone fingerprint abundant in tetraunsaturated alkenones, a hallmark of lacustrine environments. We present here the first calibration of the U37<sup>K</sup> index to temperature for a culture of P. paradoxa. We found that the U37<sup>K</sup> index accurately captured the alkenone response to temperature whereas the U37<sup>K′</sup> index failed to do so, with U37<sup>K′</sup> values below 0.08 projecting to two different temperature values. Our results add a fifth species-specific U37<sup>K</sup> calibration and provide another line of evidence that different haptophyte species require different U37<sup>K</sup> calibrations. The findings also highlight the necessary inclusion of the C<sub>37:4</sub> alkenone when reconstructing temperatures from P. paradoxa-derived alkenone records

    Non local Thirring model with backward and umklapp interactions

    Get PDF
    We extend a non local and non covariant version of the Thirring model in order to describe a many-body system with backward and umklapp scattering processes. We express the vacuum to vacuum functional in terms of a non trivial fermionic determinant. Using path-integral methods we find a bosonic representation for this determinant which allows us to obtain an effective action for the collective excitations of the system. By introducing a non local version of the self-consistent harmonic approximation, we get an expression for the gap of the charge-density excitations as functional of arbitrary electron-electron potentials. As an example we also consider the case of a non contact umklapp interaction.Comment: 19 pages, no figure
    corecore