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Presents the results of a study looking at the influence of employee participation and flexible work design on productivity change and process quality. Considers whether there is a complementary relationship between participation and flexible work design and investigates if firms employing both of these items together perform better than others.

The market’s reactions to six decisions that dealt with the employment‐at‐will doctrine were examined with event study methodology. Three hypotheses were tested, all three of which were supported clearly by the data. Shareholder returns to a sample of California firms fell in response to the three California decisions that provided at‐will employees with causes of action to challenge their discharges; returns to those same firms rose in response to the Foley decision, which cut back on the employment‐at‐will erosions in California; and, returns to a sample of firms in New York rose in response to the two decisions from New York that affirmed the supremacy of the employment‐at‐will doctrine in New York. These results support the view that employment‐at‐will is beneficial for employers and that erosions to that doctrine are costly to employers.

Introducing immunity or vaccine passports is one non-pharmaceutical intervention that governments are considering to exempt immune, vaccinated or otherwise risk-free individuals from lockdowns and other public health restrictions during the coronavirus pandemic. The primary objective of these documents would be to begin reopening societies, restarting economies and returning to a pre-pandemic normalcy. This article aims to present the start of a conceptual documentary analysis of (proposed and existing) COVID-19 immunity passports in order to more fully center their documentary status within research, considerations and conversations about their potential roles, impacts and implications.

Inspired by Paula A. Treichler's argument for the importance of theoretical thought for untangling the socio-cultural phenomena of epidemics, and drawing upon interdisciplinary theories of documentation, identity and public health, combined with recent news coverage of the coronavirus pandemic, this article provides a contemporary overview and conceptual analysis of emerging documentary regimes of COVID-19 immunity verification involving immunity or vaccine passports.

Three major interconnected objectives could be fulfilled by immunity passports. First, they would establish and materialize an official identity of COVID-19 immune for people possessing the formal document. Second, they would serve as material evidence establishing and verifying individuals' immunity, vaccination or risk-free status from the coronavirus that would, in term, determine and regulate their movements and other privileges. Third, they would create tangible links between individuals and governments' official or recognized identity category of COVID-19 immune. Immunity passports would, therefore, help enable and enforce governmental authority and power by situating individuals within documentary regimes of COVID-19 immunity verification.

In the expanding interdisciplinary literature on COVID-19 immunity passports, sometimes also called certificates, licenses, or passes, there appears to be only minimal reference to their documentary instantiations, whether physical, digital, and/or hybrid documents. As yet, there is not any specific documentary approach to or analysis of immunity passports as kinds of documentation. A documentary approach helps to illuminate and emphasize the materiality of and ontological considerations concerning the coronavirus pandemic and its associated kinds of immunity or vaccination.

By beginning an exploration of what makes immunity passports thinkable as a public health response to the coronavirus pandemic, this article illuminates these health and identity documents' material implications for, and effects on, individuals and societies. This article, therefore, helps shed light on what immunity passports reveal about the complicated and contested intersections of identity, documentation, public health and socio-political control and discipline.

This article contributes the start of a documentary analysis of (proposed and existing) COVID-19 immunity passports in order to more fully center their documentary status within research and conversations about them.

All items listed may be borrowed from the Aslib Library, except those marked, which may be consulted in the Library.

SHERRIE S. BERGMAN is College Librarian of Wheaton College in Norton, Massachusetts. She served previously as director of the Roger Williams College Library and on the library reference staff at the New School for Social Research.

The purpose of this paper is to propose a new approach for robust control of an autonomous quadrotor unmanned aerial vehicle (UAV) in automatic take-off, hovering and landing mission and also to improve the stabilizing performance of the quadrotor with inherent time-varying disturbance.

First, the dynamic model of the aerial vehicle is mathematically formulated. Then, a combination of a nonlinear backstepping scheme with the intelligent fuzzy system as a new key idea to generate a robust controller is designed for the stabilization and altitude tracking of the vehicle. For the problem of determining the backstepping control parameters, a new heuristic algorithm, namely, Gravitational Search Algorithm has been used.

The control law design utilizes the backstepping control methodology that uses Lyapunov function which can guarantee the stability of the nominal model system, whereas the intelligent system is used as a compensator to attenuate the effects caused by external disturbances. Simulation results demonstrate that the proposed control scheme can achieve favorable control performances for automatic take-off, hovering and landing mission of quadrotor UAV even in the presence of unknown perturbations.

This paper propose a new robust control design approach which incorporates the backstepping control with fuzzy system for quadrotor UAV with inherent time-varying disturbance. The originality of this work relies on the technique to compensate the disturbances acting on the quadrotor UAV. In this new approach, the fuzzy system is introduced as an auxiliary control effort to compensate the effect of disturbances. Because the proposed control technique has the capability of robustness against disturbance, thus, it is also suitable to be applied for a broad class of uncertain nonlinear systems.