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In 2021, California committed to providing universal prekindergarten (UPK) for all 4-year-olds and expanding access for income-eligible 3-year-olds by 2025-2026. California UPK includes several early learning programs, including transitional kindergarten (TK), the California State Preschool Program (CSPP), Head Start, and locally funded early learning programs. To support UPK expansion, California's legislature and administration established the Universal Prekindergarten Planning and Implementation Grant in 2021, which allocated $200 million to all local education agencies (LEAs) serving kindergarteners, which include school districts, charter schools, and county offices of education. The California Department of Education surveyed all grant recipients in August 2023 about their UPK programs. This report provides an update on UPK implementation across the state through an analysis of survey responses from 1,384 LEAs, which represent almost all (95%) public school districts and two thirds (65%) of charter schools that serve elementary grades. Findings provide insights into LEAs' progress in UPK implementation related to service delivery models, facilities and transportation, instruction and assessment, strategies to support student needs, workforce development, implementation challenges, and technical assistance needs. In addition to statewide insights, the survey revealed promising practices and wide access with UPK expansion in California's four largest districts during their first year of implementation. The findings in this report may help policymakers and practitioners identify areas for additional investments and supports.

Evidence shows that children's early years are a crucial time for their development. Well-designed early childhood education (ECE) experiences can foster meaningful gains in school readiness, as well as long-term benefits such as lower rates of special education placement and higher graduation rates. The quality of early education is highly dependent on sufficient preparation and support for early educators to meet the needs of diverse young learners. Research has identified high-quality coaching as an effective professional learning practice for supporting educators in the implementation of evidence-based practices. According to the research, effective coaching relies on a strong partnership between coaches and educators; reflection and individualized feedback; focused observations; intentional coaching plans to guide sessions; and job-embedded learning opportunities for active learning. Well-qualified coaches with knowledge of specific coaching models and practices, general coaching and consultation skills, and knowledge of early childhood development and teaching are critical as well. This report examines five early childhood coaching systems--two state systems (Alabama and Washington) and three California county systems (El Dorado, Fresno, and San Diego)--that have developed systemic coaching approaches. The researchers studied these coaching systems to understand the different ways that comprehensive coaching systems can be implemented at scale, the types of coaching approaches used, and the supports offered. Although there is no singular strategy to scale effective coaching, this research provides insights for policymakers and program administrators seeking to incorporate coaching into their efforts to improve the quality of early childhood education.

The interplay between crystal electric field splitting of d states and Hund's rule exchange energy in cobalt-based perovskites offers a promising avenue for inducing spin-state transitions. This study reports a new body-centered tetragonal (BCT) phase of BaCoO$_3$ (BCT-BaCoO$_3$), synthesized under high pressure (15 GPa) and high temperature (1200 {\deg}C) conditions. BCT-BaCoO$_3$ adopts a double perovskite structure of EuTiO$_3$-type (space group I4/mcm, #140), confirmed by high-resolution scanning transmission electron microscopy. X-ray photoelectron spectroscopy reveals a rare Co$^{4+}$ valence state. Magnetization and X-ray absorption measurements reveal a low-spin to high-spin transition that takes place between 200 and 300 K. While spin crossovers are relatively common among common oxides, the one observed in BCT-BaCoO$_3$ is remarkable in that it proceeds in the opposite direction from conventional spin transitions. BCT-BaCoO$_3$ exhibits a low-spin (S = 1/2) state at high temperatures and transitions to a high-spin (S = 5/2) state at low temperatures. Within the high-spin state, hard ferromagnetic order onsets at T$_C$ = 107 K. Electrical resistivity indicates weak magnetoresistance and insulating behavior. Overall, BCT-BaCoO$_3$ presents an exceptional model for the exploration of spin-state transitions and the study of Co spin states in cobalt-based perovskites., Comment: 22+14 pages, 5+7 figures

Planet formation is strongly influenced by the composition and distribution of volatiles within protoplanetary disks. With JWST, it is now possible to obtain direct observational constraints on disk ices, as recently demonstrated by the detection of ice absorption features towards the edge-on HH 48 NE disk as part of the Ice Age Early Release Science program. Here, we introduce a new radiative transfer modeling framework designed to retrieve the composition and mixing status of disk ices using their band profiles, and apply it to interpret the H2O, CO2, and CO ice bands observed towards the HH 48 NE disk. We show that the ices are largely present as mixtures, with strong evidence for CO trapping in both H2O and CO2 ice. The HH 48 NE disk ice composition (pure vs. polar vs. apolar fractions) is markedly different from earlier protostellar stages, implying thermal and/or chemical reprocessing during the formation or evolution of the disk. We infer low ice-phase C/O ratios around 0.1 throughout the disk, and also demonstrate that the mixing and entrapment of disk ices can dramatically affect the radial dependence of the C/O ratio. It is therefore imperative that realistic disk ice compositions are considered when comparing planetary compositions with potential formation scenarios, which will fortunately be possible for an increasing number of disks with JWST., Comment: Accepted to ApJ. 24 pages, 15 figures

Research shows that socioeconomically, racially, and ethnically integrated schools can have important benefits for student learning. While much research has focused on the benefits of integrated K-12 settings, emerging evidence indicates that the benefit of school- and classroom-level diversity may also be significant in early childhood education (ECE). Despite the positive influence of integrated settings, most ECE programs are remarkably segregated, driven by patterns of residential segregation and by policies that govern access to programs. This report explores five policy strategies that foster integration rather than segregation: (1) Establish universal ECE programs where age is the only requirement, so that family income does not determine where a child can enroll; (2) Braid public funding or combine funding streams from various sources to enable children from different socioeconomic backgrounds to learn in the same classroom; (3) Allow tuition-paying families to enroll in public programs while reserving seats for families with low incomes; (4) Attract families across neighborhoods or district boundaries; and (5) Create two-way dual language immersion programs (programs that offer instruction in two languages). These strategies can be bolstered by collecting enrollment data--disaggregated by race, ethnicity, language, and socioeconomic status--to help state and local leaders understand the extent to which children are learning in diverse classrooms. Examples are provided of how cities and school districts across the country are implementing each strategy and navigating common challenges. The strategies examined highlight ways policymakers can create enabling conditions for children from different socioeconomic, racial, and ethnic backgrounds to learn together.

Over the past decade the relation between the Balmer-line luminosity of HII galaxies and the velocity width of the emission lines, the L - {\sigma} relation, has been painstakingly calibrated as a cosmological distance indicator with seemingly spectacular results: the Hubble constant and the energy-density of dark energy obtained using the L-{\sigma} indicator agree remarkably well with the values from canonical indicators. Since most of the luminosity of these young compact starburst galaxies is emitted by a few narrow emission-lines, they can be observed with good precision up redshifts z ~ 7 with JWST, making the L - {\sigma} indicator a potentially unique cosmological probe. However, the precision of the method remains too low to effectively constrain the relevant cosmological parameters, notably the equation of state of dark energy. The scatter of the L - {\sigma} relation is significantly larger than the random observational errors so we do not have a good handle on the systematics of the method. In a previous paper we posited that since the ionizing radiation of these young galaxies fades rapidly over time-scales of only a few million years, age differences could be the main underlying cause of the scatter. In this paper we explore several different ways to explain the scatter of the correlation, but without success. We show that the majority of HII galaxies are powered by multiple starbursts of slightly different ages, and therefore that the equivalent widths are not reliable chronometers to correct the luminosities for evolution. Thus, it is not likely that the accuracy of the L - {\sigma} distance indicator can be improved in the near future. Since we do not fully understand neither the systematics nor the underlying physics of the L - {\sigma} relation, using large samples of distant HII galaxies may or may not improve the accuracy of the method., Comment: A&A accepted, 8 pages, 10 figures

Ice-coated dust grains provide the main reservoir of volatiles that play an important role in planet formation processes and may become incorporated into planetary atmospheres. However, due to observational challenges, the ice abundance distribution in protoplanetary disks is not well constrained. We present JWST/MIRI observations of the edge-on disk HH 48 NE carried out as part of the IRS program Ice Age. We detect CO$_2$, NH$_3$, H$_2$O and tentatively CH$_4$ and NH$_4^+$. Radiative transfer models suggest that ice absorption features are produced predominantly in the 50-100 au region of the disk. The CO$_2$ feature at 15 micron probes a region closer to the midplane (z/r = 0.1-0.15) than the corresponding feature at 4.3 micron (z/r = 0.2-0.6), but all observations trace regions significantly above the midplane reservoirs where we expect the bulk of the ice mass to be located. Ices must reach a high scale height (z/r ~ 0.6; corresponding to modeled dust extinction Av ~ 0.1), in order to be consistent with the observed vertical distribution of the peak ice optical depths. The weakness of the CO$_2$ feature at 15 micron relative to the 4.3 micron feature and the red emission wing of the 4.3 micron CO$_2$ feature are both consistent with ices being located at high elevation in the disk. The retrieved NH$_3$ abundance and the upper limit on the CH$_3$OH abundance relative to H$_2$O are significantly lower than those in the interstellar medium (ISM), but consistent with cometary observations. Full wavelength coverage is required to properly study the abundance distribution of ices in disks. To explain the presence of ices at high disk altitudes, we propose two possible scenarios: a disk wind that entrains sufficient amounts of dust, thus blocking part of the stellar UV radiation, or vertical mixing that cycles enough ices into the upper disk layers to balance ice photodesorption., Comment: 16 pages, 11 figures, accepted in A&A

We present the Black Hole Explorer (BHEX), a mission that will produce the sharpest images in the history of astronomy by extending submillimeter Very-Long-Baseline Interferometry (VLBI) to space. BHEX will discover and measure the bright and narrow "photon ring" that is predicted to exist in images of black holes, produced from light that has orbited the black hole before escaping. This discovery will expose universal features of a black hole's spacetime that are distinct from the complex astrophysics of the emitting plasma, allowing the first direct measurements of a supermassive black hole's spin. In addition to studying the properties of the nearby supermassive black holes M87* and Sgr A*, BHEX will measure the properties of dozens of additional supermassive black holes, providing crucial insights into the processes that drive their creation and growth. BHEX will also connect these supermassive black holes to their relativistic jets, elucidating the power source for the brightest and most efficient engines in the universe. BHEX will address fundamental open questions in the physics and astrophysics of black holes that cannot be answered without submillimeter space VLBI. The mission is enabled by recent technological breakthroughs, including the development of ultra-high-speed downlink using laser communications, and it leverages billions of dollars of existing ground infrastructure. We present the motivation for BHEX, its science goals and associated requirements, and the pathway to launch within the next decade., Comment: Proceedings for SPIE Astronomical Telescopes and Instrumentation

We present a charge self-consistent density functional theory combined with the ghost-rotationally-invariant slave-boson (DFT+gRISB) formalism for studying correlated materials. This method is applied to SrVO$_3$ and NiO, representing prototypical correlated metals and charge-transfer insulators. For SrVO$_3$, we demonstrate that DFT+gRISB yields an accurate equilibrium volume and effective mass close to experimentally observed values. Regarding NiO, DFT+gRISB enables the simultaneous description of charge transfer and Mott-Hubbard bands, significantly enhancing the accuracy of the original DFT+RISB approach. Furthermore, the calculated equilibrium volume and spectral function reasonably agree with experimental observations.

We classify closed, conformally flat Lorentzian manifolds of dimension $n \geq 3$ with unipotent holonomy in PO(2,n). They are all Kleinian and fall into four different geometric types according to the intersection of the image of the developing map with a holonomy-invariant isotropic flag. They are homeomorphic to $S^{n-1} \times S^1$ or a nilmanifold of degree at most three, up to a finite cover. We classify those admitting an essential conformal flow; these fall into two geometric types, both homeomorphic to $S^{n-1} \times S^1$ up to finite cover., Comment: 34 pages, 3 figures

SPHEREx, the Spectro-Photometer for the History of the Universe, Epoch of Reionization, and ices Explorer, is a NASA MIDEX mission planned for launch in 2024. SPHEREx will carry out the first all-sky spectral survey at wavelengths between 0.75 micron and 5 micron with spectral resolving power ~40 between 0.75 and 3.8 micron and ~120 between 3.8 and 5 micron At the end of its two-year mission, SPHEREx will provide 0.75-to-5 micron spectra of each 6.2"x6.2" pixel on the sky - 14 billion spectra in all. This paper updates an earlier description of SPHEREx presenting changes made during the mission's Preliminary Design Phase, including a discussion of instrument integration and test and a summary of the data processing, analysis, and distribution plans.

In 2021, California committed to providing universal prekindergarten (UPK) for all 4-year-olds and income-eligible 3-year-olds by 2025-26. UPK includes several early learning programs, including transitional kindergarten (TK), the California State Preschool Program (CSPP), Head Start, and expanded learning opportunities to provide full-day early learning and care. TK is the only UPK program that is free and universally available as part of California's public education system. Offered by local education agencies (LEAs), TK currently serves all 4-year-olds who turn 5 between September 2 and December 2 and will expand to all 4-year-olds by 2025-26. The legislature also made new investments in CSPP, a program for income-eligible 3- and 4-year-old children. Funding for CSPP is provided by the state through grants to both LEAs and community-based organizations. This report provides a snapshot of 1,108 LEAs' initial plans for UPK expansion through the analysis of a survey administered by the California Department of Education in August 2022. Key findings provide insights into LEA plans for service delivery models, facilities and transportation, instruction and assessment, workforce development, school leader development, and technical assistance needs. Notably: (1) Universal prekindergarten delivery models; (2) Facilities and transportation; (3) Instruction and assessment; (4) Workforce development; (5) Supporting school leaders; (6) Technical assistance needs; and (7) Large district approaches to UPK. These findings may help policymakers and practitioners identify areas for additional investments and supports during UPK implementation, although the authors note several data limitations and caution that initial UPK plans may have shifted over the course of the 2022-23 school year. As California moves forward with the expansion of universal prekindergarten, more research and data collection will be needed.

Most states in the United States operate their public preschool programs in a mixed delivery system that serves children in local education agencies (LEAs) as well as non-LEA settings, such as Head Start agencies, child care centers, private schools, and family child care homes. To inform state preschool administrators and policymakers as they refine their mixed delivery systems, this report describes the mixed delivery systems of five states that have taken different approaches to supporting providers across settings. The five states discussed in this report include: (1) Alabama; (2) Michigan; (3) New Jersey; (4) New York; and (5) West Virginia. This report answers the following questions: (1) What is the landscape of mixed delivery in select states' preschool programs? (2) How are state preschool contracts awarded, and what supports are provided to non-LEAs to participate? and (3) What are quality requirements, and who monitors and is ultimately responsible for program quality?

We present JWST MIRI MRS observations of the edge-on protoplanetary disk around the young sub-solar mass star Tau 042021, acquired as part of the Cycle 1 GO program "Mapping Inclined Disk Astrochemical Signatures (MIDAS)." These data resolve the mid-IR spatial distributions of H$_2$, revealing X-shaped emission extending to ~200 au above the disk midplane with a semi-opening angle of $35 \pm 5$ degrees. We do not velocity-resolve the gas in the spectral images, but the measured semi-opening angle of the H$_2$ is consistent with an MHD wind origin. A collimated, bipolar jet is seen in forbidden emission lines from [Ne II], [Ne III], [Ni II], [Fe II], [Ar II], and [S III]. Extended H$_2$O and CO emission lines are also detected, reaching diameters between ~90 and 190 au, respectively. Hot molecular emission is not expected at such radii, and we interpret its extended spatial distribution as scattering of inner disk molecular emission by dust grains in the outer disk surface. H I recombination lines, characteristic of inner disk accretion shocks, are similarly extended, and are likely also scattered light from the innermost star-disk interface. Finally, we detect extended PAH emission at 11.3 microns co-spatial with the scattered light continuum, making this the first low-mass T Tauri star around which extended PAHs have been confirmed, to our knowledge. MIRI MRS line images of edge-on disks provide an unprecedented window into the outflow, accretion, and scattering processes within protoplanetary disks, allowing us to constrain the disk lifetimes and accretion and mass loss mechanisms., Comment: Accepted for publication in ApJL on March 13th, 2024

Narrow bit-width data formats are key to reducing the computational and storage costs of modern deep learning applications. This paper evaluates Microscaling (MX) data formats that combine a per-block scaling factor with narrow floating-point and integer types for individual elements. MX formats balance the competing needs of hardware efficiency, model accuracy, and user friction. Empirical results on over two dozen benchmarks demonstrate practicality of MX data formats as a drop-in replacement for baseline FP32 for AI inference and training with low user friction. We also show the first instance of training generative language models at sub-8-bit weights, activations, and gradients with minimal accuracy loss and no modifications to the training recipe.

ComDMFT is a parallel computational package designed to study the electronic structure of correlated quantum materials from first principles. Our approach is based on the combination of first-principles methods and dynamical mean field theories. In version 2.0, we implemented fully-diagrammatic GW+EDMFT from first-principles. In this approach, correlated electrons are treated within full GW+EDMFT and the rest are treated within full-GW, seamlessly. This implementation enables the electronic structure calculation of quantum materials with weak, intermediate, and strong electron correlation without prior knowledge of the degree of electron correlation.

We investigate the effects of Hund's coupling on the resonant X-ray absorption spectra of the recently discovered family of layered nickelate superconductors. We contrast two scenarios depending on the relative strength of the ratio of the effective Hund's coupling ($J_H$) to the crystal fields ($\Delta$) in these systems. We carry out the cluster and DFT+DMFT simulations of the RIXS signal at the Ni $L$-edge for different values of Hund's coupling. We find the latter dominates for the parent compound while the former becomes important for sufficiently large doping. Our results are consistent with the observations of a softening of a RIXS peak as a function of doping by Rossi {\sl et al.}~\cite{PhysRevB.104.L220505}, only when the Hund coupling is sizeable. To interpret the results, we separate the theoretical RIXS signal into spin conserving and non-spin conserving channels and conclude that the infinite layer nickelates are in a regime where $\Delta$ and $J$ compete effectively and suggest further experimental tests of the theory., Comment: 6+6 pages, 5+5 figures

Ices are the main carriers of volatiles in protoplanetary disks and are crucial to our understanding of the chemistry that ultimately sets the organic composition of planets. The ERS program Ice Age on the JWST follows the ice evolution through all stages of star and planet formation. JWST/NIRSpec observations of the edge-on Class II protoplanetary disk HH~48~NE reveal spatially resolved absorption features of the major ice components H$_2$O, CO$_2$, CO, and multiple weaker signatures from less abundant ices NH$_3$, OCN$^-$, and OCS. Isotopologue $^{13}$CO$_2$ ice has been detected for the first time in a protoplanetary disk. Since multiple complex light paths contribute to the observed flux, the ice absorption features are filled in by ice-free scattered light. The $^{12}$CO$_2$/$^{13}$CO$_2$ ratio of 14 implies that the $^{12}$CO$_2$ feature is saturated, without the flux approaching 0, indicative of a very high CO$_2$ column density on the line of sight, and a corresponding abundance with respect to hydrogen that is higher than ISM values by a factor of at least a few. Observations of rare isotopologues are crucial, as we show that the $^{13}$CO$_2$ observation allows us to determine the column density of CO$_2$ to be at an order of magnitude higher than the lower limit directly inferred from the observed optical depth. Radial variations in ice abundance, e.g., snowlines, are significantly modified since all observed photons have passed through the full radial extent of the disk. CO ice is observed at perplexing heights in the disk, extending to the top of the CO-emitting gas layer. We argue that the most likely interpretation is that we observe some CO ice at high temperatures, trapped in less volatile ices like H$_2$O and CO$_2$. Future radiative transfer models will be required to constrain the implications on our current understanding of disk physics and chemistry., Comment: 16 pages, 8 figures, accepted for publication in A&A

The Nancy Grace Roman Space Telescope is capable of delivering an unprecedented all-sky, high-spatial resolution, multi-epoch infrared map to the astronomical community. This opportunity arises in the midst of numerous ground- and space-based surveys that will provide extensive spectroscopy and imaging together covering the entire sky (such as Rubin/LSST, Euclid, UNIONS, SPHEREx, DESI, SDSS-V, GALAH, 4MOST, WEAVE, MOONS, PFS, UVEX, NEO Surveyor, etc.). Roman can uniquely provide uniform high-spatial-resolution (~0.1 arcsec) imaging over the entire sky, vastly expanding the science reach and precision of all of these near-term and future surveys. This imaging will not only enhance other surveys, but also facilitate completely new science. By imaging the full sky over two epochs, Roman can measure the proper motions for stars across the entire Milky Way, probing 100 times fainter than Gaia out to the very edge of the Galaxy. Here, we propose NANCY: a completely public, all-sky survey that will create a high-value legacy dataset benefiting innumerable ongoing and forthcoming studies of the universe. NANCY is a pure expression of Roman's potential: it images the entire sky, at high spatial resolution, in a broad infrared bandpass that collects as many photons as possible. The majority of all ongoing astronomical surveys would benefit from incorporating observations of NANCY into their analyses, whether these surveys focus on nearby stars, the Milky Way, near-field cosmology, or the broader universe., Comment: Submitted to the call for white papers for the Roman Core Community Survey (June 16th, 2023), and to the Bulletin of the AAS

This study investigates the relationships between preschool quality and children's learning and development from fall to spring of 1 school year through the analysis of child- and program-level data from approximately 70,000 children, ranging in age from 4.5 to 5.5 years old, in 1,700 Quality Counts California (QCC) rated preschool programs, the majority of which were center-based California State Preschool Programs. Learning and development was assessed using children's fall and spring scores on three domains of the Desired Results Developmental Profile, a developmental assessment administered by children's classroom teachers. The authors used multiple regression models to estimate the additional months of learning and development associated with attending a higher-rated program (Tier 4 or Tier 5) above and beyond the months of learning and development projected for a child attending a program rated Tier 3. The relatively small number of programs rated Tiers 1 and 2 were excluded from the analysis. The study suggests that attending a higher-quality-rated program is associated with greater learning and development than attending a lower-quality-rated program. [This report was co-produced by the Berkeley Evaluation and Assessment Research (BEAR) Center at the University of California, Berkeley, with additional support from the California Department of Social Services.]

In 2021, California made major new investments to advance its commitment to early childhood education through universal preschool. One important investment was extending state funding for transitional kindergarten (TK), previously just for older 4-year-olds, to all 4-year-olds by 2025-26. To ensure the quality of new preschool investments, California must recruit and prepare a sufficient number of qualified teachers in TK and other early childhood programs--a challenge given the rapid expansion of the program. This challenge is even greater during the COVID-19 pandemic, when school districts and early childhood programs are facing significant staffing shortages. This report provides estimates of how many TK teachers California will need through 2025-26 and discusses potential pathways to support a diverse, well-prepared workforce, both in TK and in other early childhood programs. The authors also offer recommendations that state policymakers could follow to stabilize, support, and expand the broader early childhood workforce and to build pathways for racially, linguistically, and culturally diverse educators. [For the Research Brief, see ED622845.]