Hard and bright gamma-ray emission at the base of the Fermi bubbles

The Fermi bubbles (FBs) are large gamma-ray emitting lobes extending up to $55\deg$ in latitude above and below the Galactic center (GC). Although the FBs were discovered 8 years ago, their origin and the nature of the gamma-ray emission are still unresolved. Understanding the properties of the FBs near the Galactic plane may provide a clue to their origin. Previous analyses of the gamma-ray emission at the base of the FBs, what remains after subtraction of Galactic foregrounds, have shown an increased intensity compared to the FBs at high latitudes, a hard power-law spectrum without evidence of a cutoff up to approximately 1 TeV, and a displacement of the emission to negative longitudes relative to the GC. We analyze 9 years of Fermi Large Area Telescope data in order to study in more detail the gamma-ray emission at the base of the FBs, especially at energies above 10 GeV. We confirm that the gamma-ray emission at the base of the FBs is well described by a simple power law up to 1 TeV energies. The 95% confidence lower limit on the cutoff energy is about 500 GeV. It has larger intensity than the FBs emission at high latitudes and is shifted to the west (negative longitudes) from the GC. If the emission at the base of the FBs is indeed connected to the high-latitude FBs, then the shift of the emission to negative longitudes disfavors models where the FBs are created by the supermassive black hole at the GC. We find that the gamma-ray spectrum can be explained either by gamma rays produced in hadronic interactions or by leptonic inverse Compton scattering. In the hadronic scenario, the emission at the base of the FBs can be explained either by several hundred supernova remnants (SNRs) near the Galactic center or by about 10 SNRs at a distance of ~ 1 kpc. In the leptonic scenario, the necessary number of SNRs is a factor of a few larger than in the hadronic scenario. (abridged)Comment: 24 pages, 18 figures, published in A&

At-Risk Preschool Childrenís Exposure to Amounts and Types of Literacy Instruction.

Early reading ability critically affects children’s long-term academic outcomes. However, children from disadvantaged backgrounds tend to begin formal schooling with fewer of the key skills and abilities needed for successful reading than do their more privileged classmates. For this reason, investments have been made in targeted preschool programs that focus to a great extent on increasing at-risk children’s early language and literacy abilities. However, we know very little about the language and literacy instruction that teachers present to at-risk preschoolers in such programs. In this dissertation, I examine teacher-log data on the enacted language and literacy instruction provided in a group of Michigan state-funded preschools. I seek to shed light on: (a) the time teachers in targeted preschool programs devote to literacy instruction, (b) the literacy skills they most commonly teach to their students, (c) the extent to which they focus on key literacy skills and related instructional strategies with their students, and (d) the instructional strategies related to language and literacy development they employ within the content domain of science. My results suggest that just over 13 minutes of language and literacy instruction may be provided to the average child per half day of instruction, and that key literacy skills and instructional strategies known to predict later achievement may not be taught a large proportion of the time. These initial findings suggest a potentially problematic situation for at-risk children, who need additional instruction if they are to catch up to their more privileged peers. In this respect, the results of my dissertation may have important implications for educational change and future research.PhDEducational StudiesUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/113568/1/lherold_1.pd

Resolving the Hubble tension with Early Dark Energy

Early dark energy (EDE) offers a solution to the so-called Hubble tension. Recently, it was shown that the constraints on EDE using Markov Chain Monte Carlo are affected by prior volume effects. The goal of this paper is to present constraints on the fraction of EDE, $f_\mathrm{EDE}$, and the Hubble parameter, $H_0$, which are not subject to prior volume effects. We conduct a frequentist profile likelihood analysis considering Planck cosmic microwave background, BOSS full-shape galaxy clustering, DES weak lensing, and SH0ES supernova data. Contrary to previous findings, we find that $H_0$ for the EDE model is in statistical agreement with the SH0ES direct measurement at $\leq 1.7\,\sigma$ for all data sets. For our baseline data set (Planck + BOSS), we obtain $f_\mathrm{EDE} = 0.087\pm 0.037$ and $H_0 = 70.57 \pm 1.36\, \mathrm{km/s/Mpc}$ at $68\%$ confidence limit. We conclude that EDE is a viable solution to the Hubble tension.Comment: 6 pages, 3 figures, 1 tabl

Fostering Infant and Toddler Music Competence at the Jean Tyson Child Development Study Center

This paper presents a creative research project that introduced musical instruments in an outdoor setting to infants and toddlers ages 0-to-3 years old. It was grounded in research suggesting that music plays a vital component in expanding development in the early childhood years, helping to promote learning across many domains. This project began with a survey distributed to 7 infant and toddler classroom educators, after which responses were analyzed for themes regarding perceived infant interests. Subsequent observations were conducted to evaluate the best fit for the implementation of an outdoor experiential music space. Based on the findings, a developmentally appropriate musical space was implemented on the infant and toddler playground of the University of Arkansas Jean Tyson Child Development Study Center. Key elements of the space included a design allowing for open exploration, comfortable seating for all ages, and promoting conversations and interactions. Finally, observations were conducted to evaluate the impact of this setting on infant and toddler interactions. Qualitative analysis suggested that the new outdoor music space promoted interactions and engagement, dramatic play episodes, and the expression of emotions, which are all critical to the development of self-esteem and social-emotional competence

Fostering Infant and Toddler Music Competence at the Jean Tyson Child Development Study Center

This paper presents a creative research project that introduced musical instruments in an outdoor setting to infants and toddlers ages 0-to-3 years old. It was grounded in research suggesting that music plays a vital component in expanding development in the early childhood years, helping to promote learning across many domains. This project began with a survey distributed to 7 infant and toddler classroom educators, after which responses were analyzed for themes regarding perceived infant interests. Subsequent observations were conducted to evaluate the best fit for the implementation of an outdoor experiential music space. Based on the findings, a developmentally appropriate musical space was implemented on the infant and toddler playground of the University of Arkansas Jean Tyson Child Development Study Center. Key elements of the space included a design allowing for open exploration, comfortable seating for all ages, and promoting conversations and interactions. Finally, observations were conducted to evaluate the impact of this setting on infant and toddler interactions. Qualitative analysis suggested that the new outdoor music space promoted interactions and engagement, dramatic play episodes, and the expression of emotions, which are all critical to the development of self-esteem and social-emotional competence

Mukhanov-Sasaki equation in manifestly gauge-invariant linearized cosmological perturbation theory with dust reference fields

The aim of this article is to understand the role of dust reference fields, often also called clocks, on cosmological perturbations around a flat FLRW universe. We derive the Mukhanov-Sasaki (MS) equation for the Brown-Kuchar (BK) and Gaussian dust models, which both consider four dust fields as reference fields. The reduced phase space of Dirac observables, that is the gauge-invariant part of the theory, is constructed by means of an observable map applied to all elementary phase space variables of the coupled system, consisting of gravity, a massive scalar field and the dust degrees of freedom. The evolution of these observables is governed by a so called physical Hamiltonian which can be derived once the set of reference fields are chosen and differs for each model. First, the reduced phase space as well as the corresponding equations of motion are derived for full general relativity. Then from this, the gauge-invariant version of the equations of motion for the background are derived which contain a fingerprint of the dust reference fields. Afterwards we study linear cosmological perturbations around a FLRW metric using the scalar-vector-tensor decomposition and derive the equation of motion for the MS variable in this formalism for a chosen set of variables on the reduced phase space and expressed in terms of Dirac observables. The MS equation involves additional contributions that can be understood as back reactions from the dust reference fields. These additional dust contributions to the MS equation were absent if the dust energy and momentum density as well as their perturbations are vanishing. The nature of the correction terms suggest that BK and Gaussian dust reference fields contribute differently. Using numerical simulations we study the behavior of the dust contributions to the MS equation during inflation.Comment: Revised version. Analysis and comparison of two dust models extended to investigate Mukhanov-Sasaki variable with now corrected contribution for Brown-Kuchar model. Figures added and updated. To appear in Phys. Rev.

Creating a Culturally Competent Children’s Library

There is an ever-growing need for cultural competence and a well-rounded education, especially for children. In order to promote cultural competence, this creative project focused on enhancing a library space at the University of Arkansas Bumpers College Jean Tyson Child Development Study Center, Fayetteville, Arkansas with resources that address diversity and cultural competence. The goal was to transform the library into an enticing, relaxing, and judgment-free area where children feel comfortable to explore their culture and the cultures of others. New books added to the library were thoroughly reviewed and chosen for the purpose of promoting cultural competence and inclusion, as well as new language introduction. A wide variety of cultures from around the world, as well as over ten languages, were represented in the new reading materials. In addition to new reading materials, new furniture and decor items were also purchased to elevate the space into a comfortable area that welcomes children and invites them to explore. The hope is that in using the new space and reading books that focus on cultural competence, the children (and adult educators) will learn about different cultures

Constraint on Early Dark Energy from Isotropic Cosmic Birefringence

Polarization of the cosmic microwave background (CMB) is sensitive to new physics violating parity symmetry, such as the presence of a pseudoscalar "axionlike" field. Such a field may be responsible for early dark energy (EDE), which is active prior to recombination and provides a solution to the so-called Hubble tension. The EDE field coupled to photons in a parity-violating manner would rotate the plane of linear polarization of the CMB and produce a cross-correlation power spectrum of $E$- and $B$-mode polarization fields with opposite parities. In this paper, we fit the $EB$ power spectrum predicted by the photon-axion coupling of the EDE model with a potential $V(\phi)\propto [1-\cos(\phi/f)]^3$ to polarization data from Planck. We find that the unique shape of the predicted $EB$ power spectrum is not favored by the data and obtain a first constraint on the photon-axion coupling constant, $g=(0.04\pm 0.16)M_{\text{Pl}}^{-1}$ (68% CL), for the EDE model that best fits the CMB and galaxy clustering data. This constraint is independent of the miscalibration of polarization angles of the instrument or the polarized Galactic foreground emission. Our limit on $g$ may have important implications for embedding EDE in fundamental physics, such as string theory.Comment: 7 pages, 3 figures, 1 table. The stacked EB power spectrum is publicly available at https://github.com/LilleJohs/Observed-EB-Power-Spectru

Intercultural competence among early childhood educators

The purpose of this study was to assess and develop intercultural competence among early childhood educators. Intercultural competence is an integral part of creating a welcoming environment for all students in a classroom. It is not only the acknowledgment of individual differences but the acceptance and celebration of what makes each person an individual and member of a cultural group. This project assessed the intercultural competence of 24 early childhood educators and staff at a child development center in the mid-south. Participants completed the Intercultural Development Inventory (IDI) as pre- and post-assessments. In between assessments, our team conducted a cultural competence training workshop to advance the educators’ intercultural development skills. Based on the training and conversations with the educators, diversity books and toys were purchased and implemented into the classroom. On average, intercultural competence increased significantly over time. Overall, most educators scored in the Minimization orientation, which is the most common orientation among adults. In order to advance beyond the Minimization orientation to the Acceptance orientation, educators need additional educational opportunities, which may aid them in understanding concepts regarding power and privilege, as well as other crucial differences between cultures

A visual tool for assessing tension-resolving models in the H0H_0-σ8\sigma_8 plane

Beyond-$\Lambda$CDM models, which were proposed to resolve the "Hubble tension", often have an impact on the discrepancy in the amplitude of matter clustering, the "$\sigma_8$-tension". To explore the interplay between the two tensions, we propose a simple method to visualize the relation between the two parameters $H_0$ and $\sigma_8$: For a given extension of the $\Lambda$CDM model and data set, we plot the relation between $H_0$ and $\sigma_8$ for different amplitudes of the beyond-$\Lambda$CDM physics. We use this visualization method to illustrate the trend of selected cosmological models, including non-minimal Higgs-like inflation, early dark energy, a varying effective electron mass, an extra number of relativistic species and modified dark energy models. We envision that the proposed method could be a useful diagnostic tool to illustrate the behaviour of complex cosmological models with many parameters in the context of the $H_0$ and $\sigma_8$ tensions.Comment: 19 pages, 3 figures, 5 table