430 research outputs found

    Bibliography of Sources on Dena’ina and Cook Inlet Anthropology Through 2016

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    This version 4.3 will be the final version for this bibliography, a project that was begun in 1993 by Greg Dixon. We have intentionally excluded all potential references for the year 2017. This version is about 29 pages longer and has about 211 entries added since the previous version 3.1 of 2012. Aaron Leggett has added over fifty sources many being rare items from newpapers and magazines. Also many corrections and additions were made to entries in earlier versions.I wish to thank Kenaitze Indian Tribe and the “Dena’ina Language Revitalization Project” for their support for several projects during 2017-2018, including this Vers. 4.3. Previous versions have had partial support from "Dena'ina Archiving, Training and Access" project (NSF-OPP 0326805, 2004) and from Lake Clark National Park. I thank Katherine Arndt of Alaska & Polar Regions at UAF for her careful proofreading

    Agents of Change

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    Abstract The truth sets us free, but how do we use that freedom to light the way for others? Join the presenters for an illuminating discussion about issues that people of color who are LGBT+ face both globally and locally. Participants will leave this session with action points for being an agent of change in their own circles of influence. Summary Studies show that the majority of individuals of color who are LGBT+ reside in the South, a section of the country of which the University of Tennessee and Knoxville are a part (Human Rights Campaign, 2018). Moreover, individuals with multiple oppressed identities face greater threats than individuals with one or no oppressed identity (Crenshaw, 1989; Reynolds & Pope, 1991; Human Rights Campaign, 2018). As members and allies of the Black community seek to highlight truth, they must also recognize the many unique subpopulations of the community, including people who are LGBT+, who need specific support for the distinct challenges they face daily. This session will provide individuals the tools they need--both in facts and action plans--to support the Black LGBT+ community at the University of Tennessee, in Knoxville, and in other circles of influence. When all subpopulations are supported, the whole Black community will shine. Learning Outcomes After attending this session, participants will be able to: Describe the characteristics and common issues of people of color who are LGBT+ Recognize issues that students of color who are LGBT+ face at the University of Tennessee, Knoxville Construct action points to become an agent of change for communities of color who are LGBT+ Program Content/Outline Welcome and Introduction (5 min.) Kahoot Interactive Game (8 min.) o What do you know about communities of color who are LGBT+? Review of communities of color who are LGBT+ (7 min.) Review of the University of Tennessee’s recent LGBT+ issues (12 min.) Strategies to create an LGBT+-friendly campus for communities of color (15 min.) o Your sphere of influence o Where do we go from here? Questions (3 min.) Participant Engagement The presenters will share relevant, practical information by inviting audience members to participate in an online Kahoot game as well as a think, pair, share activity to discuss strategies and recommendations for creating a more inclusive environment for students, faculty and staff, and community members of color who are LGBT+

    Improving the precision of estimates of the frequency of rare events

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    The probability of a rare event is usually estimated directly as the number of times the event occurs divided by the total sample size. Unfortunately, the precision of this estimate is low. For typical sample sizes of N \u3c 100 in ecological studies, the coefficient of variation (cv) of this estimate of the probability of a rare event can exceed 300%. Sample sizes on the order of 103–104 observations are needed to reduce the cv to below 10%. If it is impractical or impossible to increase the sample size, auxiliary data can be used to improve the precision of the estimate. We describe four approaches for using auxiliary data to improve the precision of estimates of the probability of a rare event: (1) Bayesian analysis that includes prior information about the probability; (2) stratification that incorporates information on the heterogeneity in the population; (3) regression models that account for information correlated with the probability; and (4) inclusion of aggregated data collected at larger spatial or temporal scales. These approaches are illustrated using data on the probability of capture of vespulid wasps by the insectivorous plant Darlingtonia californica. All four methods increase the precision of the estimate relative to the simple frequency-based estimate (absolute precision = 1.26, relative precision [cv] = 70%): stratification (absolute precision = 1.10, cv = 62%); regression models (absolute precision = 1.59, cv = 55%); Bayesian analysis with an informative prior probability distribution (absolute precision = 4.28, cv = 47%); and using temporally aggregated data (absolute precision = 6.75, cv = 36%). When informative auxiliary data is available, we recommend including it when estimating the probability of rare events

    Clues to the nature of dark matter from first galaxies

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    We use thirty-eight high-resolution simulations of galaxy formation between redshift 10 and 5 to study the impact of a 3 keV warm dark matter (WDM) candidate on the high-redshift Universe. We focus our attention on the stellar mass function and the global star formation rate and consider the consequences for reionization, namely the neutral hydrogen fraction evolution and the electron scattering optical depth. We find that three different effects contribute to differentiate warm and cold dark matter (CDM) predictions: WDM suppresses the number of haloes with mass less than few 10910^9 M_{\odot}; at a fixed halo mass, WDM produces fewer stars than CDM; and finally at halo masses below 10910^9 M_{\odot}, WDM has a larger fraction of dark haloes than CDM post-reionization. These three effects combine to produce a lower stellar mass function in WDM for galaxies with stellar masses at and below 107\sim 10^7 M_{\odot}. For z>7z > 7, the global star formation density is lower by a factor of two in the WDM scenario, and for a fixed escape fraction, the fraction of neutral hydrogen is higher by 0.3 at z6z \sim 6. This latter quantity can be partially reconciled with CDM and observations only by increasing the escape fraction from 23 per cent to 34 per cent. Overall, our study shows that galaxy formation simulations at high redshift are a key tool to differentiate between dark matter candidates given a model for baryonic physics.Comment: 11 pages, 8 figures, submitted to MNRA

    NIHAO XX: The impact of the star formation threshold on the cusp-core transformation of cold dark matter haloes

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    We use cosmological hydrodynamical galaxy formation simulations from the NIHAO project to investigate the impact of the threshold for star formation on the response of the dark matter (DM) halo to baryonic processes. The fiducial NIHAO threshold, n=10cm3n=10\, {\rm cm}^{-3}, results in strong expansion of the DM halo in galaxies with stellar masses in the range 107.5<Mstar<109.5M10^{7.5} < M_{star} < 10^{9.5} M_{\odot}. We find that lower thresholds such as n=0.1n=0.1 (as employed by the EAGLE/APOSTLE and Illustris/AURIGA projects) do not result in significant halo expansion at any mass scale. Halo expansion driven by supernova feedback requires significant fluctuations in the local gas fraction on sub-dynamical times (i.e., < 50 Myr at galaxy half-light radii), which are themselves caused by variability in the star formation rate. At one per cent of the virial radius, simulations with n=10n=10 have gas fractions of 0.2\simeq 0.2 and variations of 0.1\simeq 0.1, while n=0.1n=0.1 simulations have order of magnitude lower gas fractions and hence do not expand the halo. The observed DM circular velocities of nearby dwarf galaxies are inconsistent with CDM simulations with n=0.1n=0.1 and n=1n=1, but in reasonable agreement with n=10n=10. Star formation rates are more variable for higher nn, lower galaxy masses, and when star formation is measured on shorter time scales. For example, simulations with n=10n=10 have up to 0.4 dex higher scatter in specific star formation rates than simulations with n=0.1n=0.1. Thus observationally constraining the sub-grid model for star formation, and hence the nature of DM, should be possible in the near future.Comment: 18 pages, 13 figures, accepted to MNRA

    The edge of galaxy formation III: The effects of warm dark matter on Milky Way satellites and field dwarfs

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    In this third paper of the series, we investigate the effects of warm dark matter with a particle mass of mWDM=3keVm_\mathrm{WDM}=3\,\mathrm{keV} on the smallest galaxies in our Universe. We present a sample of 21 hydrodynamical cosmological simulations of dwarf galaxies and 20 simulations of satellite-host galaxy interaction that we performed both in a Cold Dark Matter (CDM) and Warm Dark Matter (WDM) scenario. In the WDM simulations, we observe a higher critical mass for the onset of star formation. Structure growth is delayed in WDM, as a result WDM haloes have a stellar population on average two Gyrs younger than their CDM counterparts. Nevertheless, despite this delayed star formation, CDM and WDM galaxies are both able to reproduce the observed scaling relations for velocity dispersion, stellar mass, size, and metallicity at z=0z=0. WDM satellite haloes in a Milky Way mass host are more susceptible to tidal stripping due to their lower concentrations, but their galaxies can even survive longer than the CDM counterparts if they live in a dark matter halo with a steeper central slope. In agreement with our previous CDM satellite study we observe a steepening of the WDM satellites' central dark matter density slope due to stripping. The difference in the average stellar age for satellite galaxies, between CDM and WDM, could be used in the future for disentangling these two models.Comment: 10 pages, 11 figures, accepted for publication on MNRA

    Evaluation of Hand-to-Hand Bioelectrical Impedance Analysis for Estimating Percent Body Fat in Young Adults

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    Purposes were to (a) to examine the validity and precision of a hand-to-hand bioelectrical impedance analyzer (HBIA) and (b) to determine the effect of an acute sub-maximal aerobic exercise bout on HBIA percent body fat (%BF) measures. Forty-one young adults (21 women; 20 men) visited the laboratory for body composition assessment on two separate occasions. During the control session, %BF was assessed by HBIA twice, before and immediately after 30 min of rest, and once by air-displacement plethysmography (ADP), using the BOD POD, which was considered the criterion method for comparison. During the exercise session, HBIA %BF measurements were determined prior-to and immediately after 30 minutes of moderate-intensity treadmill exercise. HBIA significantly underestimated %BF in the total sample (mean difference (MD) = 1.4 ± 4.3%) and, when examined by gender, in the women (MD = 2.4 ± 4.1%). The standard errors of estimate (range 4.1-4.3%) also exceeded the recommended range for accuracy (\u3c3.5%). Following exercise, there was minimal, but statistically significant reduction in HBIA-measured %BF pre- to post-exercise for the total sample (19.6 ± 6.0 vs. 19.3 ± 6.0%; p = 0.011). HBIA underestimated %BF when compared to ADP and the individual prediction error exceeded current recommendations when assessing young adults. In addition, performing sub-maximal aerobic exercise prior to the assessment decreased the %BF estimate. When one factors the exercise-induced alterations with the currently observed tendency for HBIA to underestimate %BF, it is apparent that exercise may further reduce the accuracy of this method

    Extent of Suitable Habitats for Juvenile Striped Bass: Dynamics and Implications for Recruitment in Chesapeake Bay

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    The production of striped bass Morone saxatilis in Chesapeake Bay supports recreational and commercial fisheries along the Atlantic coast of the United States, but factors that contribute to high abundances of juvenile life stages are not fully understood. In this study, we characterized and quantified suitable and optimal habitat conditions in the Chesapeake Bay for two age groups of juvenile striped bass in discrete portions of the Bay: young-of-the-year (age-0) fish in shoreline and nearshore habitats, and resident sub-adults (age-1 to -4) in the mainstem and Bay-wide. We coupled information from 24 years of monthly fisheries surveys with hindcasts from a 3-D hydrodynamic model of the Bay and a numerical model of dissolved oxygen (DO) conditions. These models provided estimates of habitat conditions for 1996 to 2019 for 33 metrics of temperature, salinity, current speed, depth, DO, and physical features of habitats. Boosted regression trees were used to identify influential habitat covariates for each group, and those covariates were used to develop nonparametric habitat suitability models based on environmental conditions at the time and location of sampling. Habitat suitability indices (HSI), ranging from 0 (poor habitat) to 1 (high-quality habitat), were assigned to each grid in the 3-D model for each season in 1996 to 2019. We quantified suitable (HSI \u3e 0.5) and optimal (HSI \u3e 0.7) on a seasonal and annual basis, and across a range of environmental conditions (wet vs. dry years; warm vs. cool years). We also estimated the persistence of suitable habitats through time as the percent of years during which conditions were suitable at a given site; persistence allowed us to identify areas of the Bay and tidal tributaries that consistently supported suitable conditions for juvenile striped bass. Specific habitat conditions that defined suitable and optimal habitats for age-0 and age 1-4 striped bass varied across seasons and among years, reflecting changes in water quality conditions in Chesapeake Bay and changes in habitat use by striped bass during their first few years of life. Metrics of water quality, especially dissolved oxygen, were consistently identified as important covariates for juvenile striped bass; these conditions are of greater importance in determining habitat suitability than specific physical features especially for a highly mobile species and may be used to inform existing decision-support tools. In our study, we found no evidence that habitat use by striped bass in Chesapeake Bay was moderated by a strict threshold for any given covariate, and average to above-average abundances of striped bass were encountered in sub-suitable conditions; thus, habitat use resulted from a combination of abiotic, and likely biotic, conditions. Neither age group exhibited a statistically significant relationship between relative abundance and the extent of suitable habitats, however, for nearly all ages and seasons, relative abundance increased with greater extent of suitable habitats suggesting that detection of this relationship requires additional annual observations. A significant decrease in the extent of suitable habitat through time (1996 to present) was observed in spring and early summer, reflecting a change in suitable environmental conditions; with additional study years, declines in the relative abundance of age-0 and age 1-4 fish may be observed as suitability of habitats continues to decline. Given the high degree of interannual variability in abundance that is characteristic of estuarine-dependent species like striped bass, the availability and quantity of suitable and high-quality habitats at the scale of individual tributaries and Bay-wide may play an important role in production of this species

    Interventional Radiology Readiness Assessment Tool for Global Health

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    The Interventional Radiology Readiness Assessment Tool for Global Health is a new tool to methodically evaluate the environment of a medical institution for interventional radiology services given the existing infrastructure. Global health provides an exciting opportunity for interventional radiology to impact health outcomes in developing countries. A systematic and thoughtful approach to integrating interventional radiology services in the health care institutions of resource poor countries is needed in order to maximize global health efforts and outcomes. The IR Readiness Assessment Tool is available as on online form and in PDF format under Additional Files below
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