An Urban Myth? New Evidence on Equity, Adequacy, and the Efficiency of Educational Resources in Pennsylvania

How and in what ways money matters in education is a long-standing question among policymakers and education researchers. This issue is particularly salient to large, urban school districts, where debates on the organization of school often gravitate toward issues of financial resources and academic performance. Large urban districts, the story goes, spend more money per pupil but generate lower than expected results. In this policy brief, University of Pennsylvania researchers Matthew P. Steinberg and Rand Quinn present evidence that addresses the oft-told story that large urban districts, such as the School District of Philadelphia (SDP), are inefficient

Conformal properties of hyperinvariant tensor networks

We thank Santiago Oviedo-Casado, Javier Molina-Vilaplana, Matthias Volk, Sukhbinder Singh, and Michael Kastoryano for insightful discussions, as well as Alexander Jahn, Jens Eisert and Glen Evenbly for their feedback on the manuscript. J.P. is grateful for financial support from Ministerio de Ciencia, Innovación y Universidades (SPAIN), including FEDER (Grant no. PGC2018-097328-B-100) together with Fundación Séneca (Murcia, Spain) (Project no. 19882/GERM/15).M.S. wrote the main manuscript text. J.P. supervised and reviewed the manuscript.Hyperinvariant tensor networks (hyMERA) were introduced as a way to combine the successes of perfect tensor networks (HaPPY) and the multiscale entanglement renormalization ansatz (MERA) in simulations of the AdS/CFT correspondence. Although this new class of tensor network shows much potential for simulating conformal field theories arising from hyperbolic bulk manifolds with quasiperiodic boundaries, many issues are unresolved. In this manuscript we analyze the challenges related to optimizing tensors in a hyMERA with respect to some quasiperiodic critical spin chain, and compare with standard approaches in MERA. Additionally, we show two new sets of tensor decompositions which exhibit different properties from the original construction, implying that the multitensor constraints are neither unique, nor difficult to find, and that a generalization of the analytical tensor forms used up until now may exist. Lastly, we perform randomized trials using a descending superoperator with several of the investigated tensor decompositions, and find that the constraints imposed on the spectra of local descending superoperators in hyMERA are compatible with the operator spectra of several minimial model CFTs.SPAINFundación Séneca 19882/GERM/15Ministerio de Ciencia, Innovación y UniversidadesEuropean Regional Development Fund PGC2018-097328-B-10

An Urban Myth? New Evidence of Equity, Adequacy and the Efficiency of Educational Resources

In this article, we offer an empirical rejoinder to the oft-told story that large urban districts, like Philadelphia, are inefficient. We situate our study during the very short period in Pennsylvania’s recent history when efforts were dedicated to addressing the inequitable distribution of resources through a fair funding formula and to increasing the amount of resources available for education spending. Even in the presence of a funding formula, school districts like Philadelphia (SDP) with its large percentage of low-income students and English language learners were disproportionately burdened. Unsurprisingly, the SDP, like many districts across the nation, did not receive sufficient resources to educate its students. However, we find that contrary to conventional wisdom, SDP did more per pupil with the resources at its disposal than the average peer district in terms of student poverty and achievement

Holographic Codes from Hyperinvariant Tensor Networks

Holographic quantum-error correcting codes are models of bulk/boundary dualities such as the anti-de Sitter/conformal field theory (AdS/CFT) correspondence, where a higher-dimensional bulk geometry is associated with the code's logical degrees of freedom. Previous discrete holographic codes based on tensor networks have reproduced the general code properties expected from continuum AdS/CFT, such as complementary recovery. However, the boundary states of such tensor networks typically do not exhibit the expected correlation functions of CFT boundary states. In this work, we show that a new class of exact holographic codes, extending the previously proposed hyperinvariant tensor networks into quantum codes, produce the correct boundary correlation functions. This approach yields a dictionary between logical states in the bulk and the critical renormalization group flow of boundary states. Furthermore, these codes exhibit a state-dependent breakdown of complementary recovery as expected from AdS/CFT under small quantum gravity corrections.Comment: 10 pages, 7 figure

Holographic codes from hyperinvariant tensor networks

Holographic quantum-error correcting codes are models of bulk/boundary dualities such as the anti-de Sitter/conformal field theory (AdS/CFT) correspondence, where a higher-dimensional bulk geometry is associated with the code’s logical degrees of freedom. Previous discrete holographic codes based on tensor networks have reproduced the general code properties expected from continuum AdS/CFT, such as complementary recovery. However, the boundary states of such tensor networks typically do not exhibit the expected correlation functions of CFT boundary states. In this work, we show that a new class of exact holographic codes, extending the previously proposed hyperinvariant tensor networks into quantum codes, produce the correct boundary correlation functions. This approach yields a dictionary between logical states in the bulk and the critical renormalization group flow of boundary states. Furthermore, these codes exhibit a state-dependent breakdown of complementary recovery as expected from AdS/CFT under small quantum gravity corrections

Service-Learning Research Primer

This research primer, created by the IUPUI Center for Service and Learning, is designed to address the need for information on how to conduct high-quality and rigorous research on service-learning. It reviews the literature base, appropriate research methodologies and measurement procedures, and available online resources

Reduced glycogen availability is associated with increased AMPKα2 activity, nuclear AMPKα2 protein abundance, and GLUT4 mRNA expression in contracting human skeletal muscle

Glycogen availability can influence glucose transporter 4 (GLUT4) expression in skeletal muscle through unknown mechanisms. The multisubstrate enzyme AMP-activated protein kinase (AMPK) has also been shown to play an important role in the regulation of GLUT4 expression in skeletal muscle. During contraction, AMPK [alpha]2 translocates to the nucleus and the activity of this AMPK isoform is enhanced when skeletal muscle glycogen is low. In this study, we investigated if decreased pre-exercise muscle glycogen levels and increased AMPK [alpha]2 activity reduced the association of AMPK with glycogen and increased AMPK [alpha]2 translocation to the nucleus and GLUT4 mRNA expression following exercise. Seven males performed 60 min of exercise at ~70% [VO.sub.2] peak on 2 occasions: either with normal (control) or low (LG) carbohydrate pre-exercise muscle glycogen content. Muscle samples were obtained by needle biopsy before and after exercise. Low muscle glycogen was associated with elevated AMPK [alpha]2 activity and acetyl-CoA carboxylase [beta] phosphorylation, increased translocation of AMPK [alpha]2 to the nucleus, and increased GLUT4 mRNA. Transfection of primary human myotubes with a constitutively active AMPK adenovirus also stimulated GLUT4 mRNA, providing direct evidence of a role of AMPK in regulating GLUT4 expression. We suggest that increased activation of AMPK [alpha]2 under conditions of low muscle glycogen enhances AMPK [alpha]2 nuclear translocation and increases GLUT4 mRNA expression in response to exercise in human skeletal muscle. <br /

Lidar Remote Sensing Variables Predict Breeding Habitat of a Neotropical Migrant Bird

A topic of recurring interest in ecological research is the degree to which vegetation structure influences the distribution and abundance of species. Here we test the applicability of remote sensing, particularly novel use of waveform lidar measurements, for quantifying the habitat heterogeneity of a contiguous northern hardwoods forest in the northeastern United States. We apply these results to predict the breeding habitat quality, an indicator of reproductive output of a well-studied Neotropical migrant songbird, the Black-throated Blue Warbler (Dendroica caerulescens). We found that using canopy vertical structure metrics provided unique information for models of habitat quality and spatial patterns of prevalence. An ensemble decision tree modeling approach (random forests) consistently identified lidar metrics describing the vertical distribution and complexity of canopy elements as important predictors of habitat use over multiple years. Although other aspects of habitat were important, including the seasonality of vegetation cover, the canopy structure variables provided unique and complementary information that systematically improved model predictions. We conclude that canopy structure metrics derived from waveform lidar, which will be available on future satellite missions, can advance multiple aspects of biodiversity research, and additional studies should be extended to other organisms and regions