643 research outputs found
The Eternal Debate on External Law in Labor Arbitration: Where We Stand Five Decades After Meltzer v. Howlett
This article details the oft-debated issue of how labor arbitrators should reconcile collective bargaining agreements (CBAs) with public sources of law, i.e., “external law,” particularly when the plain meaning of a CBA would lead to an arbitration award in contravention of public law. This article traces the origin of the debate back to 1967, when renowned labor arbitrators Robert Howlett and Bernard Meltzer took opposing views on the matter in front of the National Academy of Arbitrators. Although Meltzer’s traditional view, that arbitrators should respect the CBA and ignore the law when the two diverge, may have been the more dominant and reasoned one in 1967, recent developments in the field of labor and employment law—namely a tremendous proliferation of employment law statutes, a shift in Supreme Court jurisprudence, and an increasingly skilled pool of arbitrators—have rendered Meltzer’s stance untenable. This article lays out four guideposts for labor arbitrators who are confronted with this challenging issue, ultimately articulating an approach that allows for measured consideration of external law to an extent that was wholly unorthodox in 1967
Pope Gregory X and the crusades
PhDThis study examines the crusading movement during the reign of Pope Gregory X in the latter part of the thirteenth century, before the Latin presence in the Levant came to an end. It seeks to demonstrate the important position of this little-known pope, who formed the bridge between what can now be seen as two separate eras in the crusading period, namely, the era of the traditional passagium generale, and the ‘new’ era of the passagium particulare. To do this, it will study Western and Muslim sources to understand the condition of the Holy Land during Gregory’s pontificate to see the effect it had on the manner in which he organised his crusade, using both traditional and ‘new’ methods. By drawing on sources from crusading in Iberia, it will show that Gregory approached the crusade flexibly, and was not, as commonly described by historians, wholly obsessed with the Holy Land. It also seeks to dispel one of the more popular myths surrounding Gregory, which is that he wanted to change the government of the kingdom of Jerusalem by putting Charles of Anjou in charge there. A study of the Angevin chancery records – little used by crusade historians – will demonstrate that it was not Gregory’s idea, but rather Charles’ own. Finally, using Gregory’s papal registers and chronicle evidence, this study will attempt to imagine the crusade that would have occurred had Gregory not died prematurely. This includes a discussion of the unprecedented scope of its recruitment as evidence of Gregory’s exceptional ability as a crusade organiser, as well as the evidence and reasons for a dramatic change in direction away from Egypt.Overseas research Students Awards Scheme provided by the British Council
TDRSS Augmentation System for Satellites
In 2015, NASA Goddard Space Flight Center (GSFC) reinvigorated the development of the TDRSS Augmentation Service for Satellites (TASS). TASS is a global, space-based, communications and navigation service for users of Global Navigation Satellite Systems(GNSS) and the Tracking and Data Relay Satellite System (TDRSS). TASS leverages the existing TDRSS to provide an S-band beacon radio navigation and messaging source to users at orbital altitudes 1400 km and below
Belief about Nicotine Selectively Modulates Value and Reward Prediction Error Signals in Smokers
Little is known about how prior beliefs impact biophysically described processes in the presence of neuroactive drugs, which presents a profound challenge to the understanding of the mechanisms and treatments of addiction. We engineered smokers\u27 prior beliefs about the presence of nicotine in a cigarette smoked before a functional magnetic resonance imaging session where subjects carried out a sequential choice task. Using a model-based approach, we show that smokers\u27 beliefs about nicotine specifically modulated learning signals (value and reward prediction error) defined by a computational model of mesolimbic dopamine systems. Belief of no nicotine in cigarette (compared with nicotine in cigarette ) strongly diminished neural responses in the striatum to value and reward prediction errors and reduced the impact of both on smokers\u27 choices. These effects of belief could not be explained by global changes in visual attention and were specific to value and reward prediction errors. Thus, by modulating the expression of computationally explicit signals important for valuation and choice, beliefs can override the physical presence of a potent neuroactive compound like nicotine. These selective effects of belief demonstrate that belief can modulate model-based parameters important for learning. The implications of these findings may be far ranging because belief-dependent effects on learning signals could impact a host of other behaviors in addiction as well as in other mental health problems
The medial habenula: still neglected
The habenula is a small, bilateral brain structure located at the dorsal end of the diencephalon. This structure sends projections to the dopaminergic striatum and receives inputs from the limbic forebrain, making the habenula a unique modulator of cross-talk between these brain regions. Despite strong interest in the habenula during the seventies and eighties (Herkenham and Nauta, 1977; Beckstead, 1979; Beckstead et al., 1979; Herkenham and Nauta, 1979; Caldecott-Hazard et al., 1988), interest waned due to lack of a clearly identifiable functional role. Following Matsumoto and Hikosaka's seminal work on the lateral habenula as a predictor of negative reward in monkeys, the habenula has undergone a resurgence of scientific interest. Matsumoto and Hikosaka demonstrated an increase in habenular neuron firing when monkeys did not receive an expected juice reward (Matsumoto and Hikosaka, 2007). Studies have shown that increased habenular activity inactivates dopaminergic cells in the Rostromedial Tegmental Nucleus (RMTg) through GABAergic mechanisms (Jhou et al., 2009a,b). Additional studies link habenular activity to the regulation of serotonin and norepinephrine, suggesting the habenula modulates multiple brain systems (Strecker and Rosengren, 1989; Amat et al., 2001). These discoveries ushered in a series of new studies that have refocused attention on the lateral habenula and the importance of this small brain structure (Bianco and Wilson, 2009; Jhou et al., 2009a; Matsumoto and Hikosaka, 2009; Sartorius et al., 2010; Savitz et al., 2011). Recently, Geisler and Trimble reviewed this renewed interest in: The Lateral Habenula: No Longer Neglected (Geisler and Trimble, 2008). While the lateral habenula (LHb) has been extensively studied, the anatomically and histochemically distinct medial habenula (MHb) remains largely understudied. This short review argues that the MHb is functionally important and should be studied more aggressively
BOLD Responses to Negative Reward Prediction Errors in Human Habenula
Although positive reward prediction error, a key element in learning that is signaled by dopamine cells, has been extensively studied, little is known about negative reward prediction errors in humans. Detailed animal electrophysiology shows that the habenula, an integrative region involved in many processes including learning, reproduction, and stress responses, also encodes negative reward-related events such as negative reward prediction error signals. In humans, however, the habenula's extremely small size has prevented direct assessments of its function. We developed a method to functionally locate and study the habenula in humans using fMRI, based on the expected reward-dependent response phenomenology of habenula and striatum and, we provide conclusive evidence for activation in human habenula to negative reward prediction errors
Characterization of a Prototype Radio Frequency Space Environment Path Emulator for Evaluating Spacecraft Ranging Hardware
The Formation Flying Testbed (FFTB) at the National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GSFC) provides a hardware-in-the-loop test environment for formation navigation and control. The facility is evolving as a modular, hybrid, dynamic simulation facility for end-to-end guidance, navigation and control (GN&C) design and analysis of formation flying spacecraft. The core capabilities of the FFTB, as a platform for testing critical hardware and software algorithms in-the-loop, have expanded to include S-band Radio Frequency (RF) modems for interspacecraft communication and ranging. To enable realistic simulations that require RF ranging sensors for relative navigation, a mechanism is needed to buffer the RF signals exchanged between spacecraft that accurately emulates the dynamic environment through which the RF signals travel, including the effects of the medium, moving platforms, and radiated power. The Path Emulator for Radio Frequency Signals (PERFS), currently under development at NASA GSFC, provides this capability. The function and performance of a prototype device are presented
Expanding Hardware-in-the-Loop Formation Navigation and Control with Radio Frequency Crosslink Ranging
The Formation Flying Testbed (FFTB) at the National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GSFC) provides a hardware-in-the-loop test environment for formation navigation and control. The facility continues to evolve as a modular, hybrid, dynamic simulation facility for end-to-end guidance, navigation, and control (GN&C) design and analysis of formation flying spacecraft. The core capabilities of the FFTB, as a platform for testing critical hardware and software algorithms in-the-loop, are reviewed with a focus on recent improvements. With the most recent improvement, in support of Technology Readiness Level (TRL) 6 testing of the Inter-spacecraft Ranging and Alarm System (IRAS) for the Magnetospheric Multiscale (MMS) mission, the FFTB has significantly expanded its ability to perform realistic simulations that require Radio Frequency (RF) ranging sensors for relative navigation with the Path Emulator for RF Signals (PERFS). The PERFS, currently under development at NASA GSFC, modulates RF signals exchanged between spacecraft. The RF signals are modified to accurately reflect the dynamic environment through which they travel, including the effects of medium, moving platforms, and radiated power
GPS Navigation for the Magnetospheric Multi-Scale Mission
In 2014. NASA is scheduled to launch the Magnetospheric Multiscale Mission (MMS), a four-satellite formation designed to monitor fluctuations in the Earth's magnetosphere. This mission has two planned phases with different orbits (1? x 12Re and 1.2 x 25Re) to allow for varying science regions of interest. To minimize ground resources and to mitigate the probability of collisions between formation members, an on-board orbit determination system consisting of a Global Positioning System (GPS) receiver and crosslink transceiver was desired. Candidate sensors would be required to acquire GPS signals both below and above the constellation while spinning at three revolutions-per-minute (RPM) and exchanging state and science information among the constellation. The Intersatellite Ranging and Alarm System (IRAS), developed by Goddard Space Flight Center (GSFC) was selected to meet this challenge. IRAS leverages the eight years of development GSFC has invested in the Navigator GPS receiver and its spacecraft communication expertise, culminating in a sensor capable of absolute and relative navigation as well as intersatellite communication. The Navigator is a state-of-the-art receiver designed to acquire and track weak GPS signals down to -147dBm. This innovation allows the receiver to track both the main lobe and the much weaker side lobe signals. The Navigator's four antenna inputs and 24 tracking channels, together with customized hardware and software, allow it to seamlessly maintain visibility while rotating. Additionally, an extended Kalman filter provides autonomous, near real-time, absolute state and time estimates. The Navigator made its maiden voyage on the Space Shuttle during the Hubble Servicing Mission, and is scheduled to fly on MMS as well as the Global Precipitation Measurement Mission (GPM). Additionally, Navigator's acquisition engine will be featured in the receiver being developed for the Orion vehicle. The crosslink transceiver is a 1/4 Watt transmitter utilizing a TDMA schedule to distribute a science quality message to all constellation members every ten seconds. Additionally the system generates one-way range measurements between formation members which is used as input to the Kalman filter. In preparation for the MMS Preliminary Design Review (PDR), the Navigator was required to pass a series of Technology Readiness Level (TRL) tests to earn the necessary TRL-6 classification. The TRL-6 level is achieved by demonstrating a prototype unit in a relevant end-to-end environment. The IRAS unit was able to meet all requirements during the testing phase, and has thus been TRL-6 qualifie
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