Sex Ratio Significance and Implications in the Cooperative Breeding Chestnut Crowned Babbler

The most simplified explanation to describe sex ratios comes from Fisher’s Principle, which assumes equal representation of both sexes following Mendelian segregation. However, violations to this principle create a biased sex ratio of more males or females. This bias has yet to be completely understood, as there have been conflicting study results. Hence, there is an importance of additional study, especially among cooperative avian species, where sex ratio variation may have greater consequences due to sexspecific dispersal and helping. One such cooperative breeder is the chestnut crowned babbler (Pomatostomus ruficeps), endemic to the Australian outback. In chestnut crowned babblers, females are generally dispersive and males philopatric. In this study blood was collected from chicks in the nest to molecularly determine the sex of each chick and examined for any sex ratio changes. This study found no significant variation in sex-ratios among chestnut crowned babblers at the population or individual levels; as well as no sex-ratio bias under six different variables – hatch date, brood size, breeding unit, number of helpers, year of birth, and number of attempts. These results are of great importance in cooperative breeding, as the ultimate goal for helpers is to pass on genetic information to continue the success of the species, even if it is not through their direct offspring. Therefore, with no significant evidence showing sex ratio bias, future studies should focus on the significance of maternal age (costs versus benefits of the sex), social status, and hatch rank

The Relation Between Ejecta Velocity, Intrinsic Color, and Host-Galaxy Mass for High-Redshift Type Ia Supernovae

Recently, using a large low-redshift sample of Type Ia supernovae (SNe Ia), we discovered a relation between SN Ia ejecta velocity and intrinsic color that improves the distance precision of SNe Ia and reduces potential systematic biases related to dust reddening. No SN Ia cosmological results have yet made a correction for the "velocity-color" relation. To test the existence of such a relation and constrain its properties at high redshift, we examine a sample of 75 SNe Ia discovered and observed by the Sloan Digital Sky Survey-II (SDSS-II) Supernova Survey and Supernova Legacy Survey (SNLS). From each spectrum, we measure ejecta velocities at maximum brightness for the Ca H&K and Si II 6355 features, v_Ca^0 and v_Si^0, respectively. Using SN light-curve parameters, we determine the intrinsic B_max - V_max for each SN. Similar to what was found at low-redshift, we find that SNe Ia with higher ejecta velocity tend to be intrinsically redder than SNe Ia with lower ejecta velocity. The distributions of ejecta velocities for SNe Ia at low and high redshift are similar, indicating that current cosmological results should have little bias related to the velocity-color relation. Additionally, we find a slight (2.4-sigma significant) trend between SN Ia ejecta velocity and host-galaxy mass such that SNe Ia in high-mass host galaxies tend to have lower ejecta velocities as probed by v_Ca^0. These results emphasize the importance of spectroscopy for SN Ia cosmology.Comment: 13 pages, 11 figures, accepted by Ap

Phosphorylation-mediated unfolding of a KH domain regulates KSRP localization via 14-3-3 binding

The AU-rich element (ARE)-mediated mRNA-degradation activity of the RNA binding K-homology splicing regulator protein (KSRP) is regulated by phosphorylation of a serine within its N-terminal KH domain (KH1). In the cell, phosphorylation promotes the interaction of KSRP and 14-3-3ζ protein and impairs the ability of KSRP to promote the degradation of its RNA targets. Here we examine the molecular details of this mechanism. We report that phosphorylation leads to the unfolding of the structurally atypical and unstable KH1, creating a site for 14-3-3ζ binding. Using this site, 14-3-3ζ discriminates between phosphorylated and unphosphorylated KH1, driving the nuclear localization of KSRP. 14-3-3ζ –KH1 interaction regulates the mRNA-decay activity of KSRP by sequestering the protein in a separate functional pool. This study demonstrates how an mRNA-degradation pathway is connected to extracellular signaling networks through the reversible unfolding of a protein domain.European Molecular Biology Organization 240-2005Italian CIPE-200

Love of Place: The Metropolitan University Advantage: 2015 CUMU National Conference in Omaha

The theme for the 2015 CUMU National Conference in Omaha, NE was “Love of Place: The Metropolitan University Advantage”. The 2015 theme celebrates key elements that establish the identity of metropolitan universities and CUMU as an organization. The theme recognizes the unique opportunities and benefits provided by metropolitan universities for students and communities. Metropolitan universities provide students with enriching educational experiences while contributing to building and strengthening the community. These enriched experiences also support faculty and staff growth as members of the university and community. The theme encouraged conference participants to explore new pedagogical approaches, strategies for sustaining meaningful partnerships, and opportunities for successful engagement of the community by examining the transformative power of the relationships between metropolitan universities and their “place.” Essential to this theme is the notion of stewardship and being good stewards of the communities that we live in, that bless our lives, our families, and our universities. The special issue devoted to the theme and notion of “Love of Place” provides an overview of the stewardship witnessed at the conference and then launches into the full article contributions that illustrate the “Love of Place” exemplified by the great presenters and the many initiatives occurring across the CUMU

The effect of progenitor age and metallicity on luminosity and 56Ni yield in Type Ia supernovae

Timmes, Brown & Truran found that metallicity variations could theoretically account for a 25% variation in the mass of 56Ni synthesized in Type Ia supernovae (SNe Ia), and thus account for a large fraction of the scatter in observed SN Ia luminosities. Higher-metallicity progenitors are more neutron-rich, producing more stable burning products relative to radioactive 56Ni. We develop a new method for estimating bolometric luminosity and 56Ni yield in SNe Ia and use it to test the theory with data from the Supernova Legacy Survey. We find that the average 56Ni yield does drop in SNe Ia from high metallicity environments, but the theory can only account for 7%--10% of the dispersion in SN Ia 56Ni mass, and thus luminosity. This is because the effect is dominant at metallicities significantly above solar, whereas we find that SN hosts have predominantly subsolar or only moderately above-solar metallicities. We also show that allowing for changes in O/Fe with the metallicity [Fe/H] does not have a major effect on the theoretical prediction of Timmes, Brown & Truran, so long as one is using the O/H as the independent variable. Age may have a greater effect than metallicity -- we find that the luminosity weighted age of the host galaxy is correlated with 56Ni yield, and thus more massive progenitors give rise to more luminous explosions. This is hard to understand if most SNe Ia explode when the primaries reach the Chandrasekhar mass. Finally, we test the findings of Gallagher et al., that the residuals of SNe Ia from the Hubble diagram are correlated with host galaxy metallicity, and we find no such correlation.Comment: ApJ, accepted, 34 pages, 11 figures, apologies for one column format -- necessary for the equation

Implementing a Holistic Approach to E-Learning Accessibility

The importance of accessibility to digital e-learning resources is widely acknowledged. The W3C WAI has played a leading role in promoting the importance of accessibility and developing guidelines which can help when developing accessible Web resources. The accessibility of e-learning resources provides additional challenges. In this paper the authors describe a holistic framework for addressing e-learning accessibility which takes into account the usability of e-learning, pedagogic issues and student learning styles in addition to technical and resource issues and provide a case study which illustrates use of this holistic approach to e-learning

Prompt Ia Supernovae Are Significantly Delayed

The time delay between the formation of a population of stars and the onset of type Ia supernovae (SNe Ia) sets important limits on the masses and nature of SN Ia progenitors. Here we use a new observational technique to measure this time delay by comparing the spatial distributions of SNe Ia to their local environments. Previous work attempted such analyses encompassing the entire host of each SN Ia, yielding inconclusive results. Our approach confines the analysis only to the relevant portions of the hosts, allowing us to show that even so-called "prompt" SNe Ia that trace star-formation on cosmic timescales exhibit a significant delay time of 200-500 million years. This implies that either the majority of Ia companion stars have main-sequence masses less than 3 solar masses, or that most SNe Ia arise from double-white dwarf binaries. Our results are also consistent with a SNe Ia rate that traces the white dwarf formation rate, scaled by a fixed efficiency factor.Comment: 6 pages, 6 figures, ApJ, in pres

Accessing Opportunities for Household Provisioning Post-COVID-19

In this project, we used a mixed-methods study to collect critical information to evaluate the extent to which people modified their shopping behavior, either by choice or necessity, to meet their provisioning needs during the COVID-19 crisis and the following recovery. First, four waves of a cross-sectional survey were administered online to a representative sample of households in Arizona, Florida, Michigan, Oregon, and Washington. This longitudinal, comparative study responded directly to a critical research gap and advanced behavioral science by providing a rich survey dataset to support and test theories of behavioral change and technology adoption. Second, focus groups were conducted with older adults in Oregon to discuss their arc of technology adoption for grocery shopping. Focus groups were also conducted with two sets of mentors who provide assistance to family members and friends with online food purchases to understand what kinds of interventions might be necessary to broaden access to e-commerce and delivery platforms for vulnerable populations. This report presents high-level descriptive statistics from these surveys comparing results by wave and/or by state. The findings from the focus groups with older adults and mentors are also described. The findings of this research are critical for emergency planning but also for understanding the ever-changing mechanism used to access retail and service opportunities (whether in-person vs. online), and the opportunities for future interventions to remedy barriers to accessing food that are relevant after the pandemic recovery

A Class of Eccentric Binaries with Dynamic Tidal Distortions Discovered with Kepler

We have discovered a class of eccentric binary systems within the Kepler data archive that have dynamic tidal distortions and tidally-induced pulsations. Each has a uniquely shaped light curve that is characterized by periodic brightening or variability at time scales of 4-20 days, frequently accompanied by shorter period oscillations. We can explain the dominant features of the entire class with orbitally-varying tidal forces that occur in close, eccentric binary systems. The large variety of light curve shapes arises from viewing systems at different angles. This hypothesis is supported by spectroscopic radial velocity measurements for five systems, each showing evidence of being in an eccentric binary system. Prior to the discovery of these 17 new systems, only four stars, where KOI-54 is the best example, were known to have evidence of these dynamic tides and tidally-induced oscillations. We perform preliminary fits to the light curves and radial velocity data, present the overall properties of this class and discuss the work required to accurately model these systems.Comment: 13 pages, submitted to Ap