Cosmology in Mirror Twin Higgs and Neutrino Masses

We explore a simple solution to the cosmological challenges of the original Mirror Twin Higgs (MTH) model that leads to interesting implications for experiment. We consider theories in which both the standard model and mirror neutrinos acquire masses through the familiar seesaw mechanism, but with a low right-handed neutrino mass scale of order a few GeV. In these $\nu$MTH models, the right-handed neutrinos leave the thermal bath while still relativistic. As the universe expands, these particles eventually become nonrelativistic, and come to dominate the energy density of the universe before decaying. Decays to standard model states are preferred, with the result that the visible sector is left at a higher temperature than the twin sector. Consequently the contribution of the twin sector to the radiation density in the early universe is suppressed, allowing the current bounds on this scenario to be satisfied. However, the energy density in twin radiation remains large enough to be discovered in future cosmic microwave background experiments. In addition, the twin neutrinos are significantly heavier than their standard model counterparts, resulting in a sizable contribution to the overall mass density in neutrinos that can be detected in upcoming experiments designed to probe the large scale structure of the universe.Comment: 22 pages, 5 figure

Are geometric morphometric analyses replicable? Evaluating landmark measurement error and its impact on extant and fossil Microtus classification.

Geometric morphometric analyses are frequently employed to quantify biological shape and shape variation. Despite the popularity of this technique, quantification of measurement error in geometric morphometric datasets and its impact on statistical results is seldom assessed in the literature. Here, we evaluate error on 2D landmark coordinate configurations of the lower first molar of five North American Microtus (vole) species. We acquired data from the same specimens several times to quantify error from four data acquisition sources: specimen presentation, imaging devices, interobserver variation, and intraobserver variation. We then evaluated the impact of those errors on linear discriminant analysis-based classifications of the five species using recent specimens of known species affinity and fossil specimens of unknown species affinity. Results indicate that data acquisition error can be substantial, sometimes explaining >30% of the total variation among datasets. Comparisons of datasets digitized by different individuals exhibit the greatest discrepancies in landmark precision, and comparison of datasets photographed from different presentation angles yields the greatest discrepancies in species classification results. All error sources impact statistical classification to some extent. For example, no two landmark dataset replicates exhibit the same predicted group memberships of recent or fossil specimens. Our findings emphasize the need to mitigate error as much as possible during geometric morphometric data collection. Though the impact of measurement error on statistical fidelity is likely analysis-specific, we recommend that all geometric morphometric studies standardize specimen imaging equipment, specimen presentations (if analyses are 2D), and landmark digitizers to reduce error and subsequent analytical misinterpretations

Analysis of Snake Creek Burial Cave Mustela fossils using Linear & Landmark-based Morphometrics: Implications for Weasel Classification & Black-footed Ferret Conservation

Two discreet methods of geometric morphometrics were applied to evaluate the taxonomic utility of each in classifying the craniomandibular region of several Mustela species. Use of both linear measurements and 2-dimensional landmarks proved successful in discriminating between extant M. nigripes (black-footed ferret) and Neovison vison (American mink), in addition to the extant North American weasel species (M. erminea, M. frenata, M. nivalis). Methods were then used to classify Late Pleistocene Mustela spp. fossils collected from Snake Creek Burial Cave (SCBC) of eastern Nevada. Data acquired for unknown predicted group memberships varied markedly among methods and specimens. Nevertheless, results support the presence of M. nigripes and all 3 weasel taxa among the SCBC paleofauna

WheelieKing Trainer Project Report

In this report we will detail the design and implementation process of the WheelieKing Trainer project, a device that helps people learn how to do wheelies on a bicycle by preventing backward falls. Formal project requirements are specified, followed by the ideation and iteration process to meet those requirements. The components and methods used to create the device are described in detail. The results of the development process and usage test results of the device are included. Appendices at the end of this report include references, supporting analyses, and project management and timeline details

Understanding the implications of a changing environment on harvested bivalve populations using habitat suitability models

Habitat suitability models are useful to forecast how environmental change may affect the abundance or distribution of species of interest. In the case of harvested bivalves, those models may be used to estimate the vulnerability of this valued ecosystem good to stressors. Using literature-derived natural history information, rule-based habitat suitability models were constructed in a GIS for several bivalve species (Clinocardium nuttallii, Mya arenaria, and Tresus capax) that are recreationally and commercially harvested in NE Pacific estuaries, including in the Salish Sea. Spatially-explicit habitat maps were produced for two Oregon estuaries using environmental data (salinity, depth, sediment grain size, and burrowing shrimp density) from multiple studies (1960-2012). Habitat suitability values ranged from 1-4 (lowest to highest) depending on the number of environmental variables that fell within a bivalve’s tolerance limits. The models were tested by comparing the observed distribution of bivalves reported in benthic community studies (1996-2012) to the range of each suitability class. Results primarily showed that habitats of highest predicted suitability contained the greatest proportion of bivalve observations and highest population densities. Our model was further supported by logistic regression analyses that showed correspondence between predicted habitat suitability values and logistic model probabilities. We demonstrate how these models can be used as tools to forecast changes in the availability of suitable habitat for these species using projected changes in salinity and depth associated with environmental change scenarios. The advantage of this approach is that disparate, independent sets of existing data are sufficient to parameterize the models, and to produce and validate maps of habitat suitability. We believe that these models are transferable across estuaries (such as in the Salish Sea) and bivalve species, and thus can be applied to data-poor systems with only modest investment

Geopier Soil Reinforcement System – Case Histories of High Bearing Capacity Footing Support and Floor Slab Support

The Geopier® Rammed Aggregate Pier system is an innovative ground improvement method developed in the 1980’s that has grown in the United States and more recently in Asia and Europe, for supporting lightly to heavily loaded structures and highway and railroad embankments. The system is unique because it prestresses and prestrains adjacent matrix soils during installation of rammed aggregate piers. It has been successfully used on hundreds of project sites to support building foundations, floor slabs, storage tanks, and roadway embankments founded on both, poor and unsuitable soils as well as fair to good soils. The rammed aggregate pier system controls settlements effectively by reinforcing soils below structures and thus improving bearing capacities and allowable bearing pressures while controlling settlements. Two case histories of specialized applications are presented in this paper: (1) Wind tower projects in Germany, where the Geopier system provides high bearing capacity and overturning moment resistances to support the foundations in soft soils; and (2) Rammed Aggregate Pier soil reinforcement support of foundations and large area floor slab system for a commercial warehouse facility in the Philippines. This paper is of particular significance because it presents case histories of a relatively new soil improvement system tailored to increase foundation bearing capacities for dynamic footing loadings and provide positive settlement control for wide area loads including floor slabs. Design and implementation of the Geopier system are presented. Evaluations of the behavior of Geopier elements based on stiffness modulus test data and an analytical approach to compare modulus test results to the design assumptions are also discussed

Reheating Metastable O'Raifeartaigh Models

In theories with multiple vacua, reheating to a temperature greater than the height of a barrier can stimulate transitions from a desirable metastable vacuum to a lower energy state. We discuss the constraints this places on various theories and demonstrate that in a class of supersymmetric models this transition does not occur even for arbitrarily high reheating temperature.Comment: 21 pages, 1 figure. Typos corrected and some references adde

Mutations in the E2 glycoprotein and the 3\u27 untranslated region enhance chikungunya virus virulence in mice

Chikungunya virus (CHIKV) is a mosquito-transmitted alphavirus that causes debilitating musculoskeletal pain and inflammation and can persist for months to years after acute infection. Although studies of humans and experimentally infected animals suggest that CHIKV infection persists in musculoskeletal tissues, the mechanisms for this remain poorly understood. To evaluate this further, we isolated CHIKV from the serum of persistently infected Rag1 -/- mice at day 28. When inoculated into naive wild-type (WT) mice, this persistently circulating CHIKV strain displayed a capacity for earlier dissemination and greater pathogenicity than the parental virus. Sequence analysis revealed a nonsynonymous mutation in the E2 glycoprotein (E2 K200R) and a deletion within the 3' untranslated region (3'-UTR). The introduction of these changes into the parental virus conferred enhanced virulence in mice, although primary tropism for musculoskeletal tissues was maintained. The E2 K200R mutation was largely responsible for enhanced viral dissemination and pathogenicity, although these effects were augmented by the 3'- UTR deletion. Finally, studies with Irf3/Irf7 -/- and Ifnar1 -/- mice suggest that the E2 K200R mutation enhances viral dissemination from the site of inoculation independently of interferon regulatory factor 3 (IRF3)-, IRF7-, and IFNAR1-mediated responses. As our findings reveal viral determinants of CHIKV dissemination and pathogenicity, their further study should help to elucidate host-virus interactions that determine acute and chronic CHIKV infection