Using Texts as Mirrors: The Power of Readers Seeing Themselves

In schools across the country and world, students enter classrooms with rich diversity in backgrounds, identities, and experiences. They speak hundreds of different languages, come from countries around the world, espouse nuanced cultural and gender identities, and have an array of abilities and interests. But texts in school and classroom collections continue to reflect the so-called mainstream with primarily White, English-dominant, cis-gendered characters without disabilities. Efforts have emerged on social media to encourage resources with relevance to children\u27s lives, but teachers often struggle to make the case for their use in instruction. In this article, we provide a framework for teachers to incorporate texts to support their unique students, drawing from existing literature and our own research on using texts as mirrors in classrooms

Solution processed graphene–silicon Schottky junction solar cells

Here, surfactant-assisted exfoliated graphene (SAEG) has been used to make transparent conducting graphene films which for the first time were used to make SAEG–silicon Schottky junctions for photovoltaics. The graphene films were characterised using UV-Vis spectroscopy, Raman spectroscopy, atomic force microscopy and four point probe sheet resistance measurements. The effects of film thickness, thermal annealing and chemical doping of the graphene films on the power conversion efficiency (PCE) of the cells were investigated. Mild annealing of thickness optimised films resulted in a doubling of the PCE. Additionally, chemical doping resulted in a further 300% increase of the peak PCE. These results indicate that SAEG has the potential to compete with chemical vapour deposited graphene in graphene–silicon Schottky junction applications.This work was supported by the Australian Microscopy and Microanalysis Research Facility (AMMRF). This work was also performed in part at the Flinders University node of the Australian National Fabrication Facility, a company established under the National Collaborative Research Infrastructure Strategy to provide nano- and micro-fabrication facilities for Australia's researchers

Passive Evolution: Are the Faint Blue Galaxy Counts Produced by a Population of Eternally Young Galaxies?

A constant age population of blue galaxies, postulated in the model of Gronwall & Koo (1995), seems to provide an attractive explanation of the excess of very blue galaxies in the deep galaxy counts. Such a population may be generated by a set of galaxies with cycling star formation rates, or at the other extreme, be maintained by the continual formation of new galaxies which fade after they reach the age specified in the Gronwall and Koo model. For both of these hypotheses, we have calculated the luminosity functions including the respective selection criteria, the redshift distributions, and the number counts in the B_J and K bands. We find a substantial excess in the number of galaxies at low redshift (0 < z < 0.05) over that observed in the CFH redshift survey (Lilly et al. 1995) and at the faint end of the Las Campanas luminosity function (Lin et al. 1996). Passive or mild evolution fails to account for the deep galaxy counts because of the implications for low redshift determinations of the I-selected redshift distribution and the r-selected luminosity function in samples where the faded counterparts of the star-forming galaxies would be detectable.Comment: 11 pages, LaTeX type (aaspp4.sty), 3 Postscript figures, submitted to ApJ Letter

Experimental observation of the dual behavior of PT{\cal PT}-symmetric scattering

We investigate experimentally parity-time (${\cal PT}$) symmetric scattering using $LRC$ circuits in an inductively coupled ${\cal PT}$- symmetric pair connected to transmission line leads. In the single-lead case, the ${\cal PT}$-symmetric circuit acts as a simple dual device - an amplifier or an absorber depending on the orientation of the lead. When a second lead is attached, the system exhibits unidirectional transparency for some characteristic frequencies. This non-reciprocal behavior is a consequence of generalized (non-unitary) conservation relations satisfied by the scattering matrix.Comment: 5 pages, 4 figure

Chronic Idiopathic Thrombocytopenic Purpura: Effective preoperative preparation and long-term results of splenectomy

A retrospective review of 98 patients seen at Henry Ford Hospital from 1953 through 1977 demonstrated that splenectomy for chronic idiopathic thrombocytopenic purpura provided a good response which usually was sustained on long-term follow-up (72% at 15 years). Although splenectomy for this condition had a low mortality, morbidity was significant in patients older than 40 years. When compared to patients whose response to splenectomy was sustained, patients who relapsed had significantly lower platelet counts preoperatively both when they were untreated (mean: 9,194 per cc versus 18,524 per-cc) and/or when they were treated with steroids (mean: 85,647 per cc versus 142,590 per cc). Another significant risk factor for relapse was a longer interval from splenectomy to the maximum postoperative platelet count. In the immediate preoperative preparation of the patient for splenectomy, corticosteroids temporarily increased the platelet count, but high doses were necessary in many patients. A platelet count of greater than 40,000/cc usually was achieved with a dose of 60 to 80 mgs of prednisone per day for several days. Platelet infusion rarely was needed if patients were prepared adequately with steroids. There should be no hesitation to give large doses of steroids for a few days, and a delay in proceeding with the operation, once indicated, should be avoided. Because the response of the platelet count to splenectomy may be variable or fluctuating and late relapses can occur, patients should be re-evaluated periodically

Quantifying Variation across 16S rRNA Gene Sequencing Runs in Human Microbiome Studies

Recent microbiome research has incorporated a higher number of samples through more participants in a study, longitudinal studies, and metanalysis between studies. Physical limitations in a sequencing machine can result in samples spread across sequencing runs. Here we present the results of sequencing nearly 1000 16S rRNA gene sequences in fecal (stabilized and swab) and oral (swab) samples from multiple human microbiome studies and positive controls that were conducted with identical standard operating procedures. Sequencing was performed in the same center across 18 different runs. The simplified mock community showed limitations in accuracy, while precision (e.g., technical variation) was robust for the mock community and actual human positive control samples. Technical variation was the lowest for stabilized fecal samples, followed by fecal swab samples, and then oral swab samples. The order of technical variation stability was inverse of DNA concentrations (e.g., highest in stabilized fecal samples), highlighting the importance of DNA concentration in reproducibility and urging caution when analyzing low biomass samples. Coefficients of variation at the genus level also followed the same trend for lower variation with higher DNA concentrations. Technical variation across both sample types and the two human sampling locations was significantly less than the observed biological variation. Overall, this research providing comparisons between technical and biological variation, highlights the importance of using positive controls, and provides semi-quantified data to better understand variation introduced by sequencing runs

Cloning Hubble Deep Fields I: A Model-Independent Measurement of Galaxy Evolution

We present a model-independent method of quantifying galaxy evolution in high-resolution images, which we apply to the Hubble Deep Field (HDF). Our procedure is to k-correct all pixels belonging to the images of a complete set of bright galaxies and then to replicate each galaxy image to higher redshift by the product of its space density, 1/V_{max}, and the cosmological volume. The set of bright galaxies is itself selected from the HDF, because presently the HDF provides the highest quality UV images of a redshift-complete sample of galaxies (31 galaxies with I<21.9, \bar{z}=0.5, and for which V/V_{max} is spread fairly). These galaxies are bright enough to permit accurate pixel-by-pixel k-corrections into the restframe UV (\sim 2000 A). We match the shot noise, spatial sampling and PSF smoothing of the HDF data, resulting in entirely empirical and parameter-free ``no-evolution'' deep fields of galaxies for direct comparison with the HDF. In addition, the overcounting rate and the level of incompleteness can be accurately quantified by this procedure. We obtain the following results. Faint HDF galaxies (I>24) are much smaller, more numerous, and less regular than our ``no-evolution'' extrapolation, for any interesting geometry. A higher proportion of HDF galaxies ``dropout'' in both U and B, indicating that some galaxies were brighter at higher redshifts than our ``cloned'' z\sim0.5 population.Comment: 51 pages, 23 figures, replacement includes figures not previously include