Exploring Implications of Brown for Schools of Choice and Raising Academic Standards

After the 1954 Brown v. Board of Education decision, policies designed to comply with the decision were often declared to be unconstitutional

Liquid film dynamics in horizontal and tilted tubes: dry spots and sliding drops

Using a model derived from lubrication theory, we consider the evolution of a thin viscous film coating the interior or exterior of a cylindrical tube. The flow is driven by surface tension and gravity and the liquid is assumed to wet the cylinder perfectly. When the tube is horizontal, we use large-time simulations to describe the bifurcation structure of the capillary equilibria appearing at low Bond number. We identify a new film configuration in which an isolated dry patch appears at the top of the tube and demonstrate hysteresis in the transition between rivulets and annular collars as the tube length is varied. For a tube tilted to the vertical, we show how a long initially uniform rivulet can break up first into isolated drops and then annular collars, which subsequently merge. We also show that the speed at which a localized drop moves down the base of a tilted tube is non-monotonic in tilt angle

Revealing the queer-spectrum in STEM: undergraduate student responses to diverse gender identity and sexual orientation demographics questions

includes bibliographical references.includes bibliographical references.Poster was to be presented at the NARST 2020 conference in Portland, Oregon, from March 15-18th, which was canceled.Queer individuals face notable heterosexist and gender-normative expectations in STEM, leading to lower persistence. However, research on the experiences of queer-spectrum individuals is limited by current demographic practices. We developed queer-inclusive demographics questions and administrated them as part of a larger study in undergraduate engineering and computer science classes. We ask: how do responses compare to nation-wide queer demographics, 3-7% for both sexual orientation and gender, and how common are heterosexist or binary-enforcing responses? In a data subset (n=314), 14% of students reported a queer sexual orientation and 1.3% of students reported a queer gender. Few students used the open-response box for gender binary-enforcing (1.3%) or heterosexist (0.3%) commentary (e.g. only two genders exist). Our high rate of queer sexual orientation responses may be explained by our broad definition of queer or differing population demographics for young adults. The low rate of queer gender identity may be due to under-representation, lack of self-reporting, or survey structure. These data will inform analysis of student experiences in our larger study. Additional work developing a research-based queered demographics instrument is needed for larger-scale changes in demographics practices, which will help others identify and address barriers that queer individuals face in STEM fields.Supported by the National Science Foundation under grant nos. 1726268, 1725880 and 1726088, as well as funding from Colorado State University's Office of the Vice President for Diversity and Walter Scott, Jr. College of Engineering

A Unified Account of the Moral Standing to Blame

Recently, philosophers have turned their attention to the question, not when a given agent is blameworthy for what she does, but when a further agent has the moral standing to blame her for what she does. Philosophers have proposed at least four conditions on having “moral standing”: 1. One’s blame would not be “hypocritical”. 2. One is not oneself “involved in” the target agent’s wrongdoing. 3. One must be warranted in believing that the target is indeed blameworthy for the wrongdoing. 4. The target’s wrongdoing must some of “one’s business”. These conditions are often proposed as both conditions on one and the same thing, and as marking fundamentally different ways of “losing standing.” Here I call these claims into question. First, I claim that conditions (3) and (4) are simply conditions on different things than are conditions (1) and (2). Second, I argue that condition (2) reduces to condition (1): when “involvement” removes someone’s standing to blame, it does so only by indicating something further about that agent, viz., that he or she lacks commitment to the values that condemn the wrongdoer’s action. The result: after we clarify the nature of the non-hypocrisy condition, we will have a unified account of moral standing to blame. Issues also discussed: whether standing can ever be regained, the relationship between standing and our "moral fragility", the difference between mere inconsistency and hypocrisy, and whether a condition of standing might be derived from deeper facts about the "equality of persons"

Dust in High Redshift Galaxies

Measurements of Zn and Cr abundances in damped Lyman alpha systems at absorption redshifts between 0.692 and 3.390 show that metals and dust are much less abundant in high redshift galaxies than in the Milky Way today. We conclude that the overall degree of metal enrichment of DLA galaxies approximately 13.5 Gyr ago is 1/15 solar. The depletion of Cr is approximately 2, significantly less than in local interstellar clouds. We propose this reflects an overall lower abundance of dust, and deduce a typical dust-to-gas ratio of 1/30 of the Milky Way value, still sufficient to explain the weakness of Lyman alpha emission from star-forming regions. We show that, despite claims to the contrary, these conclusions are not inconsistent with recent high resolution observations of DLAs with the Keck Telescope.Comment: 23 pages, LaTeX type, 1 Postscript figure Submitted to Astrophysical Journa

Small Schools: Great Strides, A Study of New Schools in Chicago

This book documents a two-year study and analysis of small schools in Chicago. Using a mixed-method study, gathering both quantitative and qualitative data, the research serves to compare results to previous studies of small urban schools.The study examines the effects of small schools on students, parents, teachers, and community members. Both previous and current research suggest that small school size is correlated with an increase in student attendance, performance, and better sense of community overall.https://educate.bankstreet.edu/books/1022/thumbnail.jp

Tracing baculovirus AcMNPV infection using a real time method based on ANCHORTM DNA labeling technology

Many steps in the baculovirus life cycle, from initial ingestion to the subsequent infection of all larval cells, remain largely unknown; primarily because it has hitherto not been possible to follow individual genomes and their lineages. Use of ANCHORTM technology allows a high intensity fluorescent labelling of DNA. When applied to a virus genome, it is possible to follow individual particles, and the overall course of infection. This technology has been adapted to enable labelling of the baculovirus Autographa californica Multiple NucleoPolyhedroVirus genome, as a first step to its application to other baculoviruses. AcMNPV was modified by inserting the two components of ANCHORTM: a specific DNA-binding protein fused to a fluorescent reporter, and the corresponding DNA recognition sequence. The resulting modified virus was stable, infectious, and replicated correctly in Spodoptera frugiperda 9 (Sf9) cells and in vivo. Both budded viruses and occlusion bodies were clearly distinguishable, and infecting cells or larvae allowed the infection process to be monitored in living cells or tissues. The level of fluorescence in the culture medium of infected cells in vitro showed a good correlation with the number of infectious budded viruses. A cassette that can be used in other baculoviruses has been designed. Altogether our results introduce for the first time the generation of autofluorescent baculovirus and their application to follow infection dynamics directly in living cells or tissues

Design and Experimental Performance of a Two Stage Partial Admission Turbine, Task B.1/B.4

A three-inch mean diameter, two-stage turbine with partial admission in each stage was experimentally investigated over a range of admissions and angular orientations of admission arcs. Three configurations were tested in which first stage admission varied from 37.4 percent (10 of 29 passages open, 5 per side) to 6.9 percent (2 open, 1 per side). Corresponding second stage admissions were 45.2 percent (14 of 31 passages open, 7 per side) and 12.9 percent (4 open, 2 per side). Angular positions of the second stage admission arcs with respect to the first stage varied over a range of 70 degrees. Design and off-design efficiency and flow characteristics for the three configurations are presented. The results indicated that peak efficiency and the corresponding isentropic velocity ratio decreased as the arcs of admission were decreased. Both efficiency and flow characteristics were sensitive to the second stage nozzle orientation angles

The Metallicity of High Redshift Galaxies: The Abundance of Zinc in 34 Damped Lyman Alpha Systems from z = 0.7 to 3.4

We report new observations of ZnII and CrII absorption lines in 10 damped \lya systems (DLAs), mostly at redshift z_{abs} \simgt 2.5 . By combining these results with those from our earlier survey (Pettini et al. 1994) and other recent data, we construct a sample of 34 measurements (or upper limits) of the Zn abundance relative to hydrogen [Zn/H]; the sample includes more than one third of the total number of DLAs known. The plot of the abundance of Zn as a function of redshift reinforces the two main findings of our previous study. (1) Damped \lya systems are mostly metal-poor, at all redshifts sampled; the column density weighted mean for the whole data set is [Zn/H] $= -1.13 \pm 0.38$ (on a logarithmic scale), or approximately 1/13 of solar. (2) There is a large spread, by up to two orders of magnitude, in the metallicities we measure at essentially the same redshifts. We propose that damped \lya systems are drawn from a varied population of galaxies of different morphological types and at different stages of chemical evolution, supporting the idea of a protracted epoch of galaxy formation. At redshifts z \simgt 2 the typical metallicity of the damped \lya systems is in agreement with expectations based on the consumption of HI gas implied by the recent measurements of $\Omega_{DLA}$ by Storrie-Lombardi et al. (1996a), and with the metal ejection rates in the universe at these epochs deduced by Madau (1996) from the ultraviolet luminosities of high redshift galaxies revealed by deep imaging surveys. There are indications in our data for an increase in the mean metallicity of the damped \lya systems from $z > 3$ to $\approx 2$, consistent with the rise in the comoving star formation rate indicated by the relative numbers of $U$ and $B$ drop-outs in the Hubble Deep Field. Although such comparisons are still tentative, it appears that these different avenues for exploring the early evolution of galaxies give a broadly consistent picture.Comment: 51 pages, LaTeX, 9 Postscript Figures. Accepted for publication in the Astrophysical Journa

Experimental Elucidation of the Life Cycle of \u3ci\u3eDrepanocephalus Spathans\u3c/i\u3e (Digenea: Echinostomatidae) with Notes on the Morphological Plasticity of \u3ci\u3eD. Spathans\u3c/i\u3e in the United States

The echinostomatid Drepanocephalus spathans (syn. Drepanocephalus auritus) parasitizes the doublecrested cormorant Phalacrocorax auritus. In North America, the marsh rams-horn snail Planorbella trivolvis and ghost rams-horn snail Biomphalaria havanensis serve as snail intermediate hosts, both of which inhabit catfish aquaculture ponds in the southeastern United States. Studies have demonstrated D. spathans exposure can be lethal to juvenile channel catfish Ictalurus punctatus. Two studies were undertaken to elucidate the life cycle of D. spathans to establish a developmental time line. In both studies, D. spathans cercariae collected from naturally infected P. trivolvis individuals were used to infect channel catfish fingerlings, which were then fed to double-crested cormorants (DCCOs) that had been pharmaceutically dewormed. In study 1, laboratory-reared P. trivolvis and B. havanensis individuals were placed in aviary ponds with experimentally infected DCCO and examined bi-weekly for release of cercariae. Trematode eggs were observed in the feces of exposed birds 3 days post-infection. Birds were sacrificed 18 days post-exposure (dpe), and gravid adults morphologically and molecularly consistent with D. spathans were recovered. Snails from the aviary pond were observed shedding D. spathans cercariae 18–54 dpe. In study 2, trematode eggs were observed in the feces of exposed DCCOs beginning 8 dpe. Once eggs were observed, birds were allowed to defecate into clean tanks containing naı¨ve laboratory-reared P. trivolvis individuals. Additionally, eggs from experimental DCCO feces were recovered by sedimentation and placed in an aquarium housing laboratory-reared P. trivolvis individuals. Birds in study 2 were sacrificed after 60 days, and gravid D. spathans specimens were recovered. Snails from the experimental DCCO tanks shed D. spathans cercariae 89–97 dpe. Lastly, trematode eggs were isolated and observed for the hatching of miracidia, which emerged on average after 16 days at ambient temperatures. No D. spathans adults were observed in control birds fed non-parasitized fish. This is the first experimental confirmation of the D. spathans life cycle, resolving previously unknown developmental time lines. In addition, the effects of fixation on adult trematode morphology were assessed, clarifying reports of pronounced morphological plasticity for D. spathans