In response to how they are compensated, mutual fund managers who are underperforming by mid-year are likely to increase the risk of their portfolios toward the year-end. We argue that an increase in the liquidity of the stocks that managers use to shift risk can lead to an increase in the size of their risky bets. This in turn hurts fund investors by increasing the costs of misaligned incentives associated with delegated portfolio management. We provide both theoretical and empirical results that are consistent with this argument. We use decimalization as an exogenous shock to liquidity to identify causal effects.
Many real-world problems are known as planning and scheduling problems, where resources must be allocated so as to optimize overall performance objectives. The traditional scheduling models consider performance indicators such as processing time, cost, and quality as optimization objectives. However, most of them do not take into account energy consumption and robustness. We focus our attention in a job-shop scheduling problem where machines can work at different speeds. It represents an extension of the classical job-shop scheduling problem, where each operation has to be executed by one machine and this machine can work at different speeds. The main goal of the paper is focused on the analysis of three important objectives (energy efficiency, robustness, and makespan) and the relationship among them. We present some analytical formulas to estimate the ratio/relationship between these parameters. It can be observed that there exists a clear relationship between robustness and energy efficiency and a clear trade-off between robustness/energy efficiency and makespan. It represents an advance in the state of the art of production scheduling, so obtaining energy-efficient solutions also supposes obtaining robust solutions, and vice versa.
This chapter serves as an introduction to this book. Section 1.1 gives a brief review on the development of biophotonics and summarises the main achievements in biophotonics due to the introduction of femtosecond pulse lasers, while Section 1.2 defines the scope of the book.
Biophotonics involves the utilisation of photons, quanta of light, to image, sense and manipulate biological matter. It provides the understanding of the fundamental interaction of photons with biological media and the application of this understanding in life sciences including biological sciences and biomedicine. In that sense, biophotonics research dates back to times when biologists started to use optical microscopy and spectroscopy with a conventional light source such as a lamp. These two forms of classic biophotonic instrument revolutionised biological research and are the classic bridge between photonics and life sciences because they provide a non-destructive way to view the two-dimensional (2D) microscopic world that human eyes cannot, as well as the function of microscopic samples through colour or spectroscopic information.
Biophotonics became a recognised new discipline after the laser was invented in 1960. Laser light is fundamentally different from conventional light in the sense that it possesses high brightness in a narrow spectral window, is highly directional, and exhibits a high degree of coherence. Since 1960, these unique features have facilitated many important applications of laser technology in biological and biomedical studies. One of the important milestones in this area is the combination of laser light with an optical microscope, which led to laser scanning confocal microscopy.
The aim of this chapter is to provide a comprehensive understanding of trapped-particle near-field scanning optical microscopy (NSOM). The principle of optical trapping and laser tweezers is briefly explained in Section 6.1. Section 6.2 summarises the motivation of using a laser-trapped microsphere as a probe in NSOM. The basic principle of trapped-particle NSOM is described in Section 6.3. Two major aspects of this technique, laser trapping performance and near-field Mie scattering of dielectric and metallic particles, are discussed in Sections 6.4 and 6.5, respectively. Experimental results on image formation in trapped-particle NSOM are described in Section 6.6. In Section 6.7, some prospects for the future development of this technique are put forward.
Photons carry momentum. When the change in momentum occurs upon reflection, refraction, transmission and absorption of a light beam, the rate of change of momentum results in a force being exerted on an object. The origin of this force can be understood from Newton's laws. A light ray that is refracted through a dielectric particle changes its direction due to the refraction process. Since light carries momentum, a change in light direction implies that there must exist a force associated with that change. The resulting force, manifested as a recoil action due to the momentum redirection, draws mesoscopic particles toward the highest photon flux in the focal region. This recoil is unnoticeable for refraction by macroobjects such as lenses, but it has a substantial and measurable influence on mesoscopic refractive objects such as small dielectric particles.
The introduction of femtosecond pulse lasers has provided numerous new methods for non-destructive diagnostic analysis of biological samples. This book is the first to provide a focused and systematic treatment of femtosecond biophotonic methods. Each chapter combines theory, practice and applications, walking the reader through imaging, manipulation and fabrication techniques. Beginning with an explanation of nonlinear and multiphoton microscopy, subsequent chapters address the techniques for optical trapping and the development of laser tweezers. In a conclusion that brings together the various topics of the book, the authors discuss the growing field of femtosecond micro-engineering. The wide range of applications for femtosecond biophotonics means this book will appeal to researchers and practitioners in the fields of biomedical engineering, biophysics, life sciences and medicine.