The Opportunity to Dream: How an Early Learning Network Implemented the Liberatory Design Process

This resource is a case study created in partnership with the Friday Institute's PEER team, entitled "The Opportunity to Dream". The study focuses on the impact of the TIP Early Learning Network's third cohort and their use of the Liberatory Design process in promoting equity and opportunity for underrepresented groups. The study highlights the positive outcomes and benefits resulting from the implementation of the Liberatory Design process, specifically in the work of Edgecombe and Wake's prototypes. The case study serves as a valuable reference for those interested in understanding the impact of using the Liberatory Design process as part of the TIP Early Learning Network

Clerking for God’s Grandfather: Chauncey Belknap’s Year with Justice Oliver Wendell Holmes, Jr.

Most of what we know about law clerks comes from the clerks themselves, usually in the form of law review articles memorializing their Justices and their clerkships or in interviews with reporters and legal scholars. In a few instances, however, law clerks have contemporaneously memorialized their experiences in diaries. These materials provide a rare window into the insular world of the Court. While the recollections contained in the diaries are often infused with youthful hero worship for their employer—in contradistinction to Justice Oliver Wendell Holmes, Jr.’s claim that no man is a hero to his valet— they offer a real-time, unfiltered peek at the personalities who populated the bench and the issues with which the Court was grappling. Just such a snapshot in time is provided by the diary of Chauncey Belknap, a remarkable Harvard Law School graduate who clerked for Justice Holmes during October Term 1915. Through Belknap’s near-daily records of his clerkship, as well as his encounters with the glittering social set of pre-war Washington, we are permitted a singular and fascinating glimpse into the colorful experience of working for one of the Court’s most famous jurists

Two-stage vs. single-stage management of patients with choledocholithiasis : meta analysis of randomized controlled trials [abstract]

Current management of choledocholithiasis involves two stage process involving ERCP and laparoscopic cholecystectomy (LC). An alternative single-stage laparoscopic treatment was introduced for these patients. Various randomized controlled trials (RCT's) done to compare these 2 modalities but with controversial results

Outcome of medical versus surgical therapies for gastroesophageal reflux disease : meta analysis of randomized controlled trials [abstract]

Gastroesophageal Reflux Disease is one of the most common chronic gastrointestinal tracts. Medical management includes use of antisecretory medications or surgical management. Randomized controlled trials have compared both forms of treatment with controversial results. Therefore, we conducted meta-analysis to compare medical versus surgical therapy of GERD

The Featureless Transmission Spectra of Two Super-puff Planets

The Kepler mission revealed a class of planets known as "super-puffs," with masses only a few times larger than Earth's but radii larger than Neptune, giving them very low mean densities. All three of the known planets orbiting the young solar-type star Kepler 51 are super-puffs. The Kepler 51 system thereby provides an opportunity for a comparative study of the structures and atmospheres of this mysterious class of planets, which may provide clues about their formation and evolution. We observed two transits each of Kepler 51b and 51d with the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope. Combining new WFC3 transit times with reanalyzed Kepler data and updated stellar parameters, we confirmed that all three planets have densities lower than 0.1 g cm⁻³. We measured the WFC3 transmission spectra to be featureless between 1.15 and 1.63 μm, ruling out any variations greater than 0.6 scale heights (assuming a H/He-dominated atmosphere), thus showing no significant water absorption features. We interpreted the flat spectra as the result of a high-altitude aerosol layer (pressure <3 mbar) on each planet. Adding this new result to the collection of flat spectra that have been observed for other sub-Neptune planets, we find support for one of the two hypotheses introduced by Crossfield & Kreidberg, that planets with cooler equilibrium temperatures have more high-altitude aerosols. We strongly disfavor their other hypothesis that the H/He mass fraction drives the appearance of large-amplitude transmission features

Structural insights into Clostridium perfringens delta toxin pore formation

Clostridium perfringens Delta toxin is one of the three hemolysin-like proteins produced by C. perfringens type C and possibly type B strains. One of the others, NetB, has been shown to be the major cause of Avian Nectrotic Enteritis, which following the reduction in use of antibiotics as growth promoters, has become an emerging disease of industrial poultry. Delta toxin itself is cytotoxic to the wide range of human and animal macrophages and platelets that present GM2 ganglioside on their membranes. It has sequence similarity with Staphylococcus aureus β-pore forming toxins and is expected to heptamerize and form pores in the lipid bilayer of host cell membranes. Nevertheless, its exact mode of action remains undetermined. Here we report the 2.4 Å crystal structure of monomeric Delta toxin. The superposition of this structure with the structure of the phospholipid-bound F component of S. aureus leucocidin (LukF) revealed that the glycerol molecules bound to Delta toxin and the phospholipids in LukF are accommodated in the same hydrophobic clefts, corresponding to where the toxin is expected to latch onto the membrane, though the binding sites show significant differences. From structure-based sequence alignment with the known structure of staphylococcal α-hemolysin, a model of the Delta toxin pore form has been built. Using electron microscopy, we have validated our model and characterized the Delta toxin pore on liposomes. These results highlight both similarities and differences in the mechanism of Delta toxin (and by extension NetB) cytotoxicity from that of the staphylococcal pore-forming toxins

A Search for Additional Planets in the NASA EPOXI Observations of the Exoplanet System GJ 436

We present time series photometry of the M dwarf transiting exoplanet system GJ 436 obtained with the the EPOCh (Extrasolar Planet Observation and Characterization) component of the NASA EPOXI mission. We conduct a search of the high-precision time series for additional planets around GJ 436, which could be revealed either directly through their photometric transits, or indirectly through the variations these second planets induce on the transits of the previously known planet. In the case of GJ 436, the presence of a second planet is perhaps indicated by the residual orbital eccentricity of the known hot Neptune companion. We find no candidate transits with significance higher than our detection limit. From Monte Carlo tests of the time series, we rule out transiting planets larger than 1.5 R_Earth interior to GJ 436b with 95% confidence, and larger than 1.25 R_Earth with 80% confidence. Assuming coplanarity of additional planets with the orbit of GJ 436b, we cannot expect that putative planets with orbital periods longer than about 3.4 days will transit. However, if such a planet were to transit, we rule out planets larger than 2.0 R_Earth with orbital periods less than 8.5 days with 95% confidence. We also place dynamical constraints on additional bodies in the GJ 436 system. Our analysis should serve as a useful guide for similar analyses for which radial velocity measurements are not available, such as those discovered by the Kepler mission. These dynamical constraints on additional planets with periods from 0.5 to 9 days rule out coplanar secular perturbers as small as 10 M_Earth and non-coplanar secular perturbers as small as 1 M_Earth in orbits close in to GJ 436b. We present refined estimates of the system parameters for GJ 436. We also report a sinusoidal modulation in the GJ 436 light curve that we attribute to star spots. [Abridged]Comment: 29 pages, 8 figures, 3 tables, accepted for publication in Ap