847 research outputs found
The Rise of Political Fact-checking How Reagan Inspired a Journalistic Movement: A Reporter's Eye View
This report uses the Washington Post as a case study to trace the rise of modern political fact-checking. It considers fact-checking as a symptom of the larger, centuries-old struggle between the political establishment and the Fourth Estate to shape the narrative that will be presented to the voters. Through devices such as "Pinocchios" and "Pants-on-Fire" verdicts, journalists have formally asserted their right to adjudicate the truth or falsehood of the carefully-constructed campaign narratives of political candidates. This represents a shift of power back to the media following a low point during the run-up to the war in Iraq when The Post and other leading newspapers failed to seriously challenge the White House line on "weapons of mass destruction."The modern-day fact checking movement can be dated back to the presidency of Ronald Reagan, who attracted widespread ridicule for his claim that trees cause four times more pollution than automobiles. The ascent of political bloggers during the 2004 campaign put additional pressure on The Post and other mainstream news outlets to upgrade their fact checking operations. The Internet has democratized the fact-checking process by making information that was previously available only through expensive news databases such as Lexis-Nexis easily accessible to bloggers without any research budget
Identifying Interaction Sites in "Recalcitrant" Proteins: Predicted Protein and Rna Binding Sites in Rev Proteins of Hiv-1 and Eiav Agree with Experimental Data
Protein-protein and protein nucleic acid interactions are vitally important
for a wide range of biological processes, including regulation of gene
expression, protein synthesis, and replication and assembly of many viruses. We
have developed machine learning approaches for predicting which amino acids of
a protein participate in its interactions with other proteins and/or nucleic
acids, using only the protein sequence as input. In this paper, we describe an
application of classifiers trained on datasets of well-characterized
protein-protein and protein-RNA complexes for which experimental structures are
available. We apply these classifiers to the problem of predicting protein and
RNA binding sites in the sequence of a clinically important protein for which
the structure is not known: the regulatory protein Rev, essential for the
replication of HIV-1 and other lentiviruses. We compare our predictions with
published biochemical, genetic and partial structural information for HIV-1 and
EIAV Rev and with our own published experimental mapping of RNA binding sites
in EIAV Rev. The predicted and experimentally determined binding sites are in
very good agreement. The ability to predict reliably the residues of a protein
that directly contribute to specific binding events - without the requirement
for structural information regarding either the protein or complexes in which
it participates - can potentially generate new disease intervention strategies.Comment: Pacific Symposium on Biocomputing, Hawaii, In press, Accepted, 200
Long term evolution of planetary systems with a terrestrial planet and a giant planet
We study the long term orbital evolution of a terrestrial planet under the
gravitational perturbations of a giant planet. In particular, we are interested
in situations where the two planets are in the same plane and are relatively
close. We examine both possible configurations: the giant planet orbit being
either outside or inside the orbit of the smaller planet. The perturbing
potential is expanded to high orders and an analytical solution of the
terrestrial planetary orbit is derived. The analytical estimates are then
compared against results from the numerical integration of the full equations
of motion and we find that the analytical solution works reasonably well. An
interesting finding is that the new analytical estimates improve greatly the
predictions for the timescales of the orbital evolution of the terrestrial
planet compared to an octupole order expansion. Finally, we briefly discuss
possible applications of the analytical estimates in astrophysical problems.Comment: Accepted for publication in MNRA
Autonomous rendezvous and docking: A commercial approach to on-orbit technology validation
The Space Automation and Robotics Center (SpARC), a NASA-sponsored Center for the Commercial Development of Space (CCDS), in conjunction with its corporate affiliates, is planning an on-orbit validation of autonomous rendezvous and docking (ARD) technology. The emphasis in this program is to utilize existing technology and commercially available components whenever possible. The primary subsystems that will be validated by this demonstration include GPS receivers for navigation, a video-based sensor for proximity operations, a fluid connector mechanism to demonstrate fluid resupply capability, and a compliant, single-point docking mechanism. The focus for this initial experiment will be expendable launch vehicle (ELV) based and will make use of two residual Commercial Experiment Transporter (COMET) service modules. The first COMET spacecraft will be launched in late 1992 and will serve as the target vehicle. The ARD demonstration will take place in late 1994, after the second COMET spacecraft has been launched. The service module from the second COMET will serve as the chase vehicle
Clues to the formation of spiral structure in M51 from the ages and locations of star clusters
We determine the spatial distributions of star clusters at different ages in the grand-design spiral galaxy M51 using a new catalog based on multi-band images taken with the Hubble Space Telescope (HST). These distributions, when compared with the spiral structure defined by molecular gas, dust, young and old stars, show the following sequence in the inner arms: dense molecular gas (and dust) defines the inner edge of the spiral structure, followed by an overdensity of old stars and then young stellar clusters. The offset between gas and young clusters in the inner arms is consistent with the expectations for a density wave. Clusters as old as a few hundred Myr remain concentrated close to the spiral arms, although the distributions are broader than those for the youngest clusters, which is also consistent with predictions from density wave simulations. The outermost portion of the west arm is different from the rest of the spiral structure in that it contains primarily intermediate-age (approximate to 100-400 Myr) clusters; we believe that this is a "material" arm. We have identified four "feathers," stellar structures beyond the inner arms that have a larger pitch angle than the arms. We do not find age gradients along any of the feathers, but the least coherent feathers appear to have the largest range of cluster ages
Adaptation of frequency-domain readout for Transition Edge Sensor bolometers for the POLARBEAR-2 Cosmic Microwave Background experiment
The POLARBEAR-2 CosmicMicrowave Background (CMB) experiment aims to observe
B-mode polarization with high sensitivity to explore gravitational lensing of
CMB and inflationary gravitational waves. POLARBEAR-2 is an upgraded experiment
based on POLARBEAR-1, which had first light in January 2012. For POLARBEAR-2,
we will build a receiver that has 7,588 Transition Edge Sensor (TES) bolometers
coupled to two-band (95 and 150 GHz) polarization-sensitive antennas. For the
large array's readout, we employ digital frequency-domain multiplexing and
multiplex 32 bolometers through a single superconducting quantum interference
device (SQUID). An 8-bolometer frequency-domain multiplexing readout has been
deployed on POLARBEAR-1 experiment. Extending that architecture to 32
bolometers requires an increase in the bandwidth of the SQUID electronics to 3
MHz. To achieve this increase in bandwidth, we use Digital Active Nulling (DAN)
on the digital frequency multiplexing platform. In this paper, we present
requirements and improvements on parasitic inductance and resistance of
cryogenic wiring and capacitors used for modulating bolometers. These
components are problematic above 1 MHz. We also show that our system is able to
bias a bolometer in its superconducting transition at 3 MHz
Advanced Stirling Radioisotope Generator Engineering Unit 2 Anomaly Investigation
The Advanced Stirling Radioisotope Generator (ASRG) Engineering Unit 2 (EU2) is the highest fidelity electrically heated Stirling radioisotope generator built to date. NASA Glenn Research Center completed the assembly of the ASRG EU2 in September 2014 using hardware from the now cancelled ASRG flight development project. The ASRG EU2 integrated the first pair of Sunpower's Advanced Stirling Convertors (ASCE3 #1 and #2) in an aluminum generator housing with Lockheed Martin's (LM's) Engineering Development Unit (EDU) 4 controller. After just 179 hr of EU2 generator operation, the first power fluctuation occurred on ASCE3 #1. The first power fluctuation occurred 175 hr later on ASCE3 #2. Over time, the power fluctuations became more frequent on both convertors and larger in magnitude. Eventually the EU2 was shut down in January 2015. An anomaly investigation was chartered to determine root cause of the power fluctuations and other anomalous observations. A team with members from Glenn, Sunpower, and LM conducted a thorough investigation of the EU2 anomalies. Findings from the EU2 disassembly identified proximate causes of the anomalous observations. Discussion of the team's assessment of the primary possible failure theories, root cause, and conclusions is provided. Recommendations are made for future Stirling generator development to address the findings from the anomaly investigation. Additional findings from the investigation are also discussed
Generalized quantifiers in distributed databases.
Optimizing queries in a distributed database is quite difficult. This work proposes defining new generalized quantifiers which operate on sets rather than tuples. These quantifiers would allow for easier optimization in a horizontally distributed database. These operators are scalable with respect to both the number of hosts in the environment and the size of the data used
A Thanksgiving without Family: A Covid-19 Employer Dilemma Case
Based on an actual organization in the Midwest, this case describes the Director of an alcohol and drug rehabilitation center located in the Midwest and her adoption of policies to address the threat of Covid-19 to employees, clients, and the community. Names have been changed, but the facts of the case are based on employee descriptions of the organization, its director, and its new policies. The case presents students with an opportunity to wrestle with real-world situations that they themselves have faced and with which they are familiar. In this paper, I present the case itself, the worksheet assignment for students, the grading rubric used, and describe how it is used in the course
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