Regioselective reactions of 3,4-pyridynes enabled by the aryne distortion model.

The pyridine heterocycle continues to play a vital role in the development of human medicines. More than 100 currently marketed drugs contain this privileged unit, which remains highly sought after synthetically. We report an efficient means to access di- and trisubstituted pyridines in an efficient and highly controlled manner using transient 3,4-pyridyne intermediates. Previous efforts to employ 3,4-pyridynes for the construction of substituted pyridines were hampered by a lack of regiocontrol or the inability to later manipulate an adjacent directing group. The strategy relies on the use of proximal halide or sulfamate substituents to perturb pyridyne distortion, which in turn governs regioselectivities in nucleophilic addition and cycloaddition reactions. After trapping of the pyridynes generated in situ, the neighbouring directing groups may be removed or exploited using versatile metal-catalysed cross-coupling reactions. This methodology now renders 3,4-pyridynes as useful synthetic building blocks for the creation of highly decorated derivatives of the medicinally privileged pyridine heterocycle

Do Shareholders' Preferences Affect their Funds' Management? Evidence from the Cross Section of Shareholders and Funds

We consider how fund managers respond to the conflicting preferences of their investors. We focus on the conflict between the taxable and retirement accounts of international funds, which face different tradeoffs between dividends and capital gains. In principle, managers could resolve this conflict through dividend arbitrage, but a proprietary database of dividend-arbitrage transactions shows that in practice they cannot. Thus, managers must resolve it through their investment policies, and we find robust evidence that managers with more retirement money favor the preferences of retirement investors. We find additional evidence in the difference between U.S. and Canadian funds' portfolio weights. Nous étudions comment les gestionnaires de fonds réagissent aux préférences contradictoires de leurs investisseurs. Notre étude se concentre principalement sur les conflits entre les comptes taxés et les comptes de retraite des fonds internationaux qui font l'objet de compromis différents entre les gains en dividendes et les gains de capital. En théorie, les gestionnaires peuvent résoudre ces conflits par des opérations d'arbitrage sur les dividendes, mais une base de données privée d'opérations d'arbitrage fait apparaître qu'en pratique ils ne peuvent pas. Les gestionnaires doivent alors résoudre ces conflits à travers leurs politiques d'investissement, et nous trouvons des résultats significatifs montrant que ceux dont le capital est issu majoritairement des retraites favorisent les investisseurs de fonds de pension. Nous trouvons également des différences entre les poids des portefeuilles de fonds américains et canadiens.Dividend arbitrage, tax efficiency, agency issues, mutual funds, arbitrage sur les dividendes, taxes sur les rendements, placements pour compte, fonds commun de placement

Editorial Essay: Introduction to a Special Issue on Work and Employment Relations in Health Care

[Excerpt] This special issue of the ILR Review is designed to showcase the central role that work organization and employment relations play in shaping important outcomes such as the quality of care and organizational performance. Each of the articles included in this special issue makes an important contribution to our understanding of the large and rapidly changing health care sector. Specifically, these articles provide novel empirical evidence about the relationship between organizations, institutions, and work practices and a wide array of central outcomes across different levels of analysis. This breadth is especially important because the health care literature has largely neglected employment-related factors in explaining organizational and worker outcomes in this industry. Individually, these articles shed new light on the role that health information technologies play in affecting patient care and productivity (see Hitt and Tambe; Meyerhoefer et al.); the relationship between work practices and organizational reliability (Vogus and Iacobucci); staffing practices, processes, and outcomes (Kramer and son; Hockenberry and Becker; Kossek et al.); health care unions’ effects on the quality of patient care (Arindrajit, Kaplan, and Thompson); and the relationship between the quality of jobs and the quality of care (Burns, Hyde, and Killet). Below, we position the articles in this special issue against the backdrop of the pressures and challenges facing the industry and the organizations operating within it. We highlight the implications that organizational responses to industry pressures have had for organizations, the patients they care for, and the employees who deliver this care

How and Why do Investors Trade Votes, and What Does it Mean?

The standard analysis of corporate governance is that shareholders vote in the ratios that firms choose, such as one-share-one-vote. But if the cost of unbundling and trading votes is sufficiently low, then shareholders vote in the ratios that they themselves choose. We document an active market for votes within the equity-loan market, where we find that the average vote sells for zero. We hypothesize that asymmetric information motivates these vote reallocations, and we find support for this view in the cross section of votes: there is more trade for higher-spread firms and more for poor performers, especially when the vote is close. We also find that the vote reallocations correspond to support for shareholder proposals and opposition to management proposals. L'analyse classique de la gouvernance d'entreprise suppose que les actionnaires votent selon les modalités choisies par la firme, par exemple un vote par action. Mais si les coûts associés à la séparation et à l'échange des votes sont suffisamment faibles, alors les actionnaires votent selon les modalités qu'ils ont eux-mêmes choisies. Nous présentons le cas d'un marché actif de votes au sein du marché des mises de fonds sous forme d'emprunts (equity loans), où nous constatons qu'en moyenne les votes se vendent pour rien. Nous supposons que l'asymétrie d'information provoque cette réallocation des votes, et nous étayons cette hypothèse à travers l'étude transversale des votes : le nombre d'opérations est plus important pour les compagnies dont l'écart acheteur-vendeur est plus élevé ainsi que pour celles dont les résultats sont plus faibles, particulièrement lorsque le vote est clos. Cette étude montre aussi que la réallocation des votes permet de soutenir les propositions des actionnaires et de s'opposer à celles des gestionnaires.vote trading, corporate governance, equity lending, information asymmetry, transaction de votes, gouvernance d'entreprise, prêt d'actions, asymétrie d'information

Beam Propagation Through Atmospheric Turbulence Using an Altitude-Dependent Structure Profile with Non-Uniformly Distributed Phase Screens

For free-space optical communication systems, numerical wave optics simulations provide a useful technique for modeling turbulence-induced beam degradation when the analytical theory is insufficient for characterizing the atmospheric channel. Motivated by such applications we use a split-step method modeling the turbulence as a series of random phase screens using the Hufnagel-Valley turbulence profile. We employ a space-to-ground case study to examine the irradiance and phase statistics for uniformly and non-uniformly located screens and find better agreement with theory using a non-uniform discretization minimizing the contribution of each screen to the total scintillation. In this poster, we summarize the method and the results of the case study including a comparison to layered models used in astronomical imaging applications

Beam Propagation Through Atmospheric Turbulence Using an Altitude-Dependent Structure Profile with Non-Uniformly Distributed Phase Screens

Modeling the effects of atmospheric turbulence on optical beam propagation is a key element in the design and analysis of free-space optical communication systems. Numerical wave optics simulations provide a particularly useful technique for understanding the degradation of the optical field in the receiver plane when the analytical theory is insufficient for characterizing the atmospheric channel. Motivated by such an application, we use a split-step method modeling the turbulence along the propagation path as a series of thin random phase screens with modified von Karman refractive index statistics using the Hufnagel-Valley turbulence profile to determine the effective structure constant for each screen. In this work, we employ a space-to-ground case study to examine the irradiance and phase statistics for both uniformly and non-uniformly spaced screens along the propagation path and compare to analytical results. We find that better agreement with the analytical theory is obtained using a non-uniform spacing with the effective structure constant for each screen chosen to minimize its contribution to the scintillation in the receiver plane. We evaluate this method as a flexible alternative to other standard layered models used in astronomical imaging applications

Multiple Input-Multiple Output Cycle-to-Cycle Control of Manufacturing Processes

Cycle-to-cycle control is a method for using feedback to improve product quality for processes that are inaccessible within a single processing cycle. This limitation stems from the impossibility or the prohibitively high cost of placing sensors and actuators that could facilitate control during, or within, the process cycle. Our previous work introduced cycle to cycle control for single input-single output systems, and here it is extended to multiple input-multiple output systems. Gain selection, stability, and process noise amplification results are developed and compared with those obtained by previous researchers, showing good agreement. The limitation of imperfect knowledge of the plant model is then imposed. This is consistent with manufacturing environments where the cost and number of tests to determine a valid process model is desired to be minimal. The implications of this limitation are modes of response that are hidden from the controller. Their effects on system performance and stability are discussed.Singapore-MIT Alliance (SMA