113 research outputs found

    Module categories for AnA_n web categories from A~n−1\tilde{A}_{n-1}-buildings

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    We equip the category of vector bundles over the vertices of a locally finite A~n−1\tilde{A}_{n-1} building Δ\Delta with the structure of a module category over a category of type AnA_{n} webs in positive characteristic. This module category is a qq-analogue of the Rep(SLn)Rep(SL_{n}) action on vector bundles over the slnsl_n weight lattice. We show our module categories are equivariant with respect to symmetries of the building, and when a group GG acts simply transitively on the vertices of Δ\Delta this recovers the fiber functors constructed by Jones.Comment: 29 pages. Author contact: [email protected]

    Evaluating Established Methods for Rumen 16S rRNA Amplicon Sequencing With Mock Microbial Populations

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    peer-reviewedThe rumen microbiome scientific community has utilized amplicon sequencing as an aid in identifying potential community compositional trends that could be used as an estimation of various production and performance traits including methane emission, animal protein production efficiency, and ruminant health status. In order to translate rumen microbiome studies into executable application, there is a need for experimental and analytical concordance within the community. The objective of this study was to assess these factors in relation to selected currently established methods for 16S phylogenetic community analysis on a microbial community standard (MC) and a DNA standard (DS; ZymoBIOMICSTM). DNA was extracted from MC using the RBBC method commonly used for microbial DNA extraction from rumen digesta samples. 16S rRNA amplicon libraries were generated for the MC and DS using primers routinely used for rumen bacterial and archaeal community analysis. The primers targeted the V4 and V3–V4 region of the 16S rRNA gene and samples were subjected to both 20 and 28 polymerase chain reaction (PCR) cycles under identical cycle conditions. Sequencing was conducted using the Illumina MiSeq platform. As the bacteria contained in the microbial mock community were well-classified species, and for ease of explanation, we used the results of the Basic Local Alignment Search Tool classification to assess the DNA, PCR cycle number, and primer type. Sequence classification methodology was assessed independently. Spearman’s correlation analysis indicated that utilizing the repeated bead beating and column method for DNA extraction in combination with primers targeting the 16S rRNA gene using 20 first-round PCR cycles was sufficient for amplicon sequencing to generate a relatively accurate depiction of the bacterial communities present in rumen samples. These results also emphasize the requirement to develop and utilize positive mock community controls for all rumen microbiomic studies in order to discern errors which may arise at any step during a next-generation sequencing protocol

    Attachment, Self-Esteem and Life Satisfaction Among Survivors of Sexual Trauma

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    Survivors of sexual trauma often have unresolved attachment status, characterized by fears of abandonment, difficulty trusting others, and challenges establishing and maintaining close relationships (Bailey, Moran, & Pederson, 2007). Further, adolescents who experience sexual relations that are not grounded in a strong relationship experience increased vulnerability to depression and low self-esteem. This poster presentation will address the topic of attachment, sexual self-esteem, and life satisfaction for survivors of sexual trauma

    Raising forward osmosis brine concentration efficiency through flow rate optimization

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    An exergetic efficiency is defined in order to compare brine concentration processes including forward osmosis (FO) across a wide range of salinities. We find that existing FO pilot plants have lower efficiency than reverse osmosis plants in the brackish and seawater salinity ranges. High salinity FO, in its current form, is still less efficient than mechanical vapor compression. We show that efficiency is the product of FO exchanger and draw regenerator efficiencies, and therefore FO system energy efficiency benefits from improvements to both. The mass flow rate ratio (between draw and feed flow rates) is identified as a crucial parameter in the design of efficient FO systems because of its effect on exchanger efficiency. We demonstrate a method of thermodynamically balancing an FO system by choosing flow rates that lead to equal osmotic pressure differences at both ends of the exchanger, and show the method's potential to increase the efficiency of current systems by 3–21%.Center for Clean Water and Clean Energy at MIT and KFUPM (Project R4-CW-08)National Science Foundation (U.S.). Graduate Research Fellowship (Grant 1122374)Hugh Hampton Young Memorial Fellowshi

    Surface Gravities for 228 M, L, and T Dwarfs in the NIRSPEC Brown Dwarf Spectroscopic Survey

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    We combine 131 new medium-resolution (R~2000) J-band spectra of M, L, and T dwarfs from the Keck NIRSPEC Brown Dwarf Spectroscopic Survey (BDSS) with 97 previously published BDSS spectra to study surface-gravity-sensitive indices for 228 low-mass stars and brown dwarfs spanning spectral types M5-T9. Specifically, we use an established set of spectral indices to determine surface gravity classifications for all M6-L7 objects in our sample by measuring equivalent widths (EW) of the K I lines at 1.1692, 1.1778, 1.2529 um, and the 1.2 um FeHJ absorption index. Our results are consistent with previous surface gravity measurements, showing a distinct double peak - at ~L5 and T5 - in K I EW as a function of spectral type. We analyze K I EWs of 73 objects of known ages and find a linear trend between log(Age) and EW. From this relationship, we assign age ranges to the very low gravity, intermediate gravity, and field gravity designations for spectral types M6-L0. Interestingly, the ages probed by these designations remain broad, change with spectral type, and depend on the gravity sensitive index used. Gravity designations are useful indicators of the possibility of youth, but current datasets cannot be used to provide a precise age estimate.Comment: 33 pages, 13 figures, ApJ in pres

    Plane of nutrition affects the phylogenetic diversity and relative abundance of transcriptionally active methanogens in the bovine rumen

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    peer-reviewedMethane generated during enteric fermentation in ruminant livestock species is a major contributor to global anthropogenic greenhouse gas emissions. A period of moderate feed restriction followed by ad libitum access to feed is widely applied in cattle management to exploit the animal’s compensatory growth potential and reduce feed costs. In the present study, we utilised microbial RNA from rumen digesta samples to assess the phylogenetic diversity of transcriptionally active methanogens from feed-restricted and non-restricted animals. To determine the contribution of different rumen methanogens to methanogenesis during dietary restriction of cattle, we conducted high-throughput mcrA cDNA amplicon sequencing on an Illumina MiSeq and analysed both the abundance and phylogenetic origin of different mcrA cDNA sequences. When compared to their unrestricted contemporaries, in feed-restricted animals, the methanogenic activity, based on mcrA transcript abundance, of Methanobrevibacter gottschalkii clade increased while the methanogenic activity of the Methanobrevibacter ruminantium clade and members of the Methanomassiliicoccaceae family decreased. This study shows that the quantity of feed consumed can evoke large effects on the composition of methanogenically active species in the rumen of cattle. These data potentially have major implications for targeted CH4 mitigation approaches such as anti-methanogen vaccines and/or tailored dietary management

    Prevalence and correlates of substance use in Black, White, and biracial Black–White adolescents: Evidence for a biracial intermediate phenomena.

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    Most substance-use prevention interventions are based on the implicit assumption that risk and protective factors for substance use are the same for biracial and monoracial youth. However, preliminary research suggests this assumption may be untrue. This study compared the prevalence and correlates of substance use among Black, White, and biracial Black-White youth. Data were derived from the National Longitudinal Study of Adolescent and Adult Health (Add Health), which is a longitudinal investigation using stratified random sampling to study health behaviors. After controlling for sociodemographic factors and using weighted Poisson and logistic regression, we found the substance-use prevalence rates of Black-White youth to be intermediate to the higher rates of Whites and lower rates of Blacks. In addition, Black-White youth’s scores on most covariates were intermediate to those of the monoracial groups. Family factors were more important in explaining higher substance use than other contextual factors. School factors seem to be important in explaining lower substance use for Black-White youth. Correlates of substance use for Black-White youth were not identical to those of either Black or White youth. More research on the observed intermediate phenomena among biracial youth vis-à-vis prevalence, correlates, and causes of substance use is needed

    Gender-Based Violence Is a Human Rights Violation: Are Donors Responding Adequately? What a Decade of Donor Interventions in Colombia, Kenya, and Uganda Reveals

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    Gender-based violence (GBV) is a violation of human rights and must be addressed as such. This paper examines whether donor practices align with a rights-based approach, using data from our comprehensive study of foreign funding flows related to GBV in Colombia, Kenya, and Uganda from 2010 to 2020. By analyzing data from 1,180 grants—and providing parallel analyses of the state of GBV, and GBV reporting and interventions in each country—we demonstrate donors’ role in shaping GBV outcomes and their consequent duty to address policies and practices that violate rights. Accordingly, we propose changes in donor practices to promote realization of the right to freedom from violence

    The NIRSPEC Brown Dwarf Spectroscopic Survey II: High-Resolution J-Band Spectra of M, L and T Dwarfs

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    We present a sequence of high resolution (R~20,000 or 15 km/s) infrared spectra of stars and brown dwarfs spanning spectral types M2.5 to T6. Observations of 16 objects were obtained using eight echelle orders to cover part of the J-band from 1.165-1.323 micron with NIRSPEC on the Keck II telescope. By comparing opacity plots and line lists, over 200 weak features in the J-band are identified with either FeH or H2O transitions. Absorption by FeH attains maximum strength in the mid-L dwarfs, while H2O absorption becomes systematically stronger towards later spectral types. Narrow resolved features broaden markedly after the M to L transition. Our high resolution spectra also reveal that the disappearance of neutral Al lines at the boundary between M and L dwarfs is remarkably abrupt, presumably because of the formation of grains. Neutral Fe lines can be traced to mid-L dwarfs before Fe is removed by condensation. The neutral potassium (K I) doublets that dominate the J-band have pressure broadened wings that continue to broaden from ~50 km/s (FWHM) at mid-M to ~500 km/s at mid-T. In contrast however, the measured pseudo-equivalent widths of these same lines reach a maximum in the mid-L dwarfs. The young L2 dwarf, G196-3B, exhibits narrow potassium lines without extensive pressure-broadened wings, indicative of a lower gravity atmosphere. Kelu-1AB, another L2, has exceptionally broad infrared lines, including FeH and H2O features, confirming its status as a rapid rotator. In contrast to other late T objects, the peculiar T6 dwarf 2MASS 0937+29 displays a complete absence of potassium even at high resolution, which may be a metallicity effect or a result of a cooler, higher-gravity atmosphere.Comment: 53 pages, 21 figures, data will be available at http://www.astro.ucla.edu/~mclean/BDSSarchive

    Moving from ‘what we know works’ to ‘what we do in practice’::An evidence overview of implementation and diffusion of innovation in transition to adulthood for care experienced young people

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    Global research has shown that most young people who are care experienced are not prepared to transition to independent living at 18 years of age and require support into early adulthood. We used rigorous systematic methods to identify English‐based peer reviewed and grey literature describing innovations relevant to care experienced young people as they transition into adulthood, with a focus upon lessons for their implementation and diffusion. We synthesised the evidence narratively and organise data linked to seven key areas important to the transition to adulthood: (1) Health and well‐being; (2) relationships; (3) education and training; (4) employment; (5) participation in society; (6) accommodation; (7) other. Twenty‐five papers met our inclusion criteria. This review has found that, whilst there are a broad spectrum of innovations taking place within the social care environment for care experienced young people to support their transition into adulthood, there exists limited insight into how best to support implementation and diffusion of evidence‐based innovation. We drew upon the ‘Consolidated Framework for Implementation Research’, developed in the setting of clinical service delivery, to highlight challenges in implementing and diffusing evidence‐based innovation for care experienced young people transitioning into adulthood
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