123 research outputs found

    The Ugly Side of America: Institutional Oppression and Race

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    This manuscript examines structural racism through a socio-historical context of institutional oppression and its effects on modern society. The epistemological framework of intersectionality is used to focus on the overlap of oppression, structural racism, and implicit bias evident in the stereotypes and perceptions of the African American male population in the United States. Four eras of socio-historical significance are addressed: 1. Foundations of Racial Oppression; 2. Racism: Reconstruction and Jim Crow; 3. Renewal: Civil Rights and Civil Disobedience; 3. Reckoning: Embedded Racism and the Criminal Justice System

    Parvalbumin Interneurons of Hippocampus Tune Population Activity at Theta Frequency

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    SummaryHippocampal theta rhythm arises from a combination of recently described intrinsic theta oscillators and inputs from multiple brain areas. Interneurons expressing the markers parvalbumin (PV) and somatostatin (SOM) are leading candidates to participate in intrinsic rhythm generation and principal cell (PC) coordination in distal CA1 and subiculum. We tested their involvement by optogenetically activating and silencing PV or SOM interneurons in an intact hippocampus preparation that preserves intrinsic connections and oscillates spontaneously at theta frequencies. Despite evidence suggesting that SOM interneurons are crucial for theta, optogenetic manipulation of these interneurons modestly influenced theta rhythm. However, SOM interneurons were able to strongly modulate temporoammonic inputs. In contrast, activation of PV interneurons powerfully controlled PC network and rhythm generation optimally at 8 Hz, while continuously silencing them disrupted theta. Our results thus demonstrate a pivotal role of PV but not SOM interneurons for PC synchronization and the emergence of intrinsic hippocampal theta

    Assessment of the Activity of Ceftaroline Against Clinical Isolates of Penicillin-Intermediate and Penicillin-Resistant \u3cem\u3eStreptococcus pneumoniae\u3c/em\u3e with elevated MICs of Ceftaroline Using an In Vitro Pharmacodynamic Model

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    Objectives This study assessed the pharmacodynamics of ceftaroline against penicillin-intermediate and penicillin-resistant Streptococcus pneumoniae with elevated MICs of ceftaroline using an in vitro pharmacodynamic model. Methods Nine isolates of S. pneumoniae, including one penicillin-susceptible isolate, one penicillin-intermediate isolate and seven penicillin-resistant isolates, were tested. The pharmacodynamic model was inoculated with a concentration of 1 × 106 cfu/mL and ceftaroline was dosed twice daily (at 0 and 12 h) to simulate the fCmax (maximum free concentration in serum) and t1/2 (half-life in serum) obtained after 600 mg intravenous doses every 12 h (fCmax, 16 mg/L; t1/2, 2.6 h). Ceftaroline was compared with ceftriaxone dosed once daily to simulate the fCmax and t1/2 obtained after a 1 g dose (fCmax, 18 mg/L; t1/2, 8.0 h). Samples were collected over 24 h to assess viable growth and possible changes in ceftaroline MICs over time. Results Ceftaroline fT\u3eMIC (time of free serum concentration over the MIC) of 100% (ceftaroline MICs, ≤0.5 mg/L) was bactericidal (≥3 log10 killing) against all isolates at 6 h and completely eradicated all organisms at 12 and 24 h. No bacterial regrowth occurred over the study period and no changes in ceftaroline MICs were observed. Upon ceftriaxone exposure, S. pneumoniae isolates with ceftriaxone MICs of 0.12 and 0.25 mg/L were eradicated, but isolates with ceftriaxone MICs of 1–8 mg/L resulted in initial bacterial reduction at 6 h with organism regrowth at 12 h and no reduction in organism concentration, relative to the starting inoculum, at 24 h. Conclusions Ceftaroline fT\u3eMIC of 100% (ceftaroline MICs, ≤0.5 mg/L) was bactericidal (≥3 log10 killing) and eradicated all S. pneumoniae at 12 and 24 h with no regrowth

    Photometric Supernova Cosmology with BEAMS and SDSS-II

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    Supernova cosmology without spectroscopic confirmation is an exciting new frontier which we address here with the Bayesian Estimation Applied to Multiple Species (BEAMS) algorithm and the full three years of data from the Sloan Digital Sky Survey II Supernova Survey (SDSS-II SN). BEAMS is a Bayesian framework for using data from multiple species in statistical inference when one has the probability that each data point belongs to a given species, corresponding in this context to different types of supernovae with their probabilities derived from their multi-band lightcurves. We run the BEAMS algorithm on both Gaussian and more realistic SNANA simulations with of order 10^4 supernovae, testing the algorithm against various pitfalls one might expect in the new and somewhat uncharted territory of photometric supernova cosmology. We compare the performance of BEAMS to that of both mock spectroscopic surveys and photometric samples which have been cut using typical selection criteria. The latter typically are either biased due to contamination or have significantly larger contours in the cosmological parameters due to small data-sets. We then apply BEAMS to the 792 SDSS-II photometric supernovae with host spectroscopic redshifts. In this case, BEAMS reduces the area of the (\Omega_m,\Omega_\Lambda) contours by a factor of three relative to the case where only spectroscopically confirmed data are used (297 supernovae). In the case of flatness, the constraints obtained on the matter density applying BEAMS to the photometric SDSS-II data are \Omega_m(BEAMS)=0.194\pm0.07. This illustrates the potential power of BEAMS for future large photometric supernova surveys such as LSST.Comment: 25 pages, 15 figures, submitted to Ap

    Results from the Supernova Photometric Classification Challenge

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    We report results from the Supernova Photometric Classification Challenge (SNPCC), a publicly released mix of simulated supernovae (SNe), with types (Ia, Ibc, and II) selected in proportion to their expected rate. The simulation was realized in the griz filters of the Dark Energy Survey (DES) with realistic observing conditions (sky noise, point-spread function and atmospheric transparency) based on years of recorded conditions at the DES site. Simulations of non-Ia type SNe are based on spectroscopically confirmed light curves that include unpublished non-Ia samples donated from the Carnegie Supernova Project (CSP), the Supernova Legacy Survey (SNLS), and the Sloan Digital Sky Survey-II (SDSS-II). A spectroscopically confirmed subset was provided for training. We challenged scientists to run their classification algorithms and report a type and photo-z for each SN. Participants from 10 groups contributed 13 entries for the sample that included a host-galaxy photo-z for each SN, and 9 entries for the sample that had no redshift information. Several different classification strategies resulted in similar performance, and for all entries the performance was significantly better for the training subset than for the unconfirmed sample. For the spectroscopically unconfirmed subset, the entry with the highest average figure of merit for classifying SNe~Ia has an efficiency of 0.96 and an SN~Ia purity of 0.79. As a public resource for the future development of photometric SN classification and photo-z estimators, we have released updated simulations with improvements based on our experience from the SNPCC, added samples corresponding to the Large Synoptic Survey Telescope (LSST) and the SDSS, and provided the answer keys so that developers can evaluate their own analysis.Comment: accepted by PAS
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