Demand and revenue implications of an integrated public transport policy. The case of

One of the most popular options for promoting public transport use is the provision of an integrated and high quality public transport system. This was the strategy adopted by the regional government in Madrid in 1986 and since then public transport patronage has increased by more than 50%. This paper has two objectives. The first is to identify the factors underlying the significant increase in the demand for public transport in Madrid. To do this we estimate an aggregate demand function for bus and underground trips, which allows us to obtain the demand elasticities with respect to the main attributes of public transport services and also to calculate the long-term impact of changes in those explanatory variables on patronage. The second objective is to evaluate the impact on revenue derived from the introduction of the travel card scheme, and to discuss the consequences on revenue of changes in the relative fare levels of different types of ticket without substantially affecting patronage. This latter issue is addressed by estimating a matrix of own and cross-price elasticities for different ticket types.

A counterexample to the DeMarco-Kahn Upper Tail Conjecture

Given a fixed graph H, what is the (exponentially small) probability that the number X_H of copies of H in the binomial random graph G_{n,p} is at least twice its mean? Studied intensively since the mid 1990s, this so-called infamous upper tail problem remains a challenging testbed for concentration inequalities. In 2011 DeMarco and Kahn formulated an intriguing conjecture about the exponential rate of decay of \Pr(X_H \ge (1+\epsilon) \E X_H) for fixed \epsilon>0. We show that this upper tail conjecture is false, by exhibiting an infinite family of graphs violating the conjectured bound.Comment: 15 pages; minor edits; to appear in Random Structures and Algorithms (RSA

Efficient Scene Text Localization and Recognition with Local Character Refinement

An unconstrained end-to-end text localization and recognition method is presented. The method detects initial text hypothesis in a single pass by an efficient region-based method and subsequently refines the text hypothesis using a more robust local text model, which deviates from the common assumption of region-based methods that all characters are detected as connected components. Additionally, a novel feature based on character stroke area estimation is introduced. The feature is efficiently computed from a region distance map, it is invariant to scaling and rotations and allows to efficiently detect text regions regardless of what portion of text they capture. The method runs in real time and achieves state-of-the-art text localization and recognition results on the ICDAR 2013 Robust Reading dataset

Ostrogradsky in Theories with Multiple Fields

We review how the (absence of) Ostrogradsky instability manifests itself in theories with multiple fields. It has recently been appreciated that when multiple fields are present, the existence of higher derivatives may not automatically imply the existence of ghosts. We discuss the connection with gravitational theories like massive gravity and beyond Horndeski which manifest higher derivatives in some formulations and yet are free of Ostrogradsky ghost. We also examine an interesting new class of Extended Scalar-Tensor Theories of gravity which has been recently proposed. We show that for a subclass of these theories, the tensor modes are either not dynamical or are infinitely strongly coupled. Among the remaining theories for which the tensor modes are well-defined one counts one new model that is not field-redefinable to Horndeski via a conformal and disformal transformation but that does require the vacuum to break Lorentz invariance. We discuss the implications for the effective field theory of dark energy and the stability of the theory.Comment: references update

A Gift of Life Deserves Compensation: How to Increase Living Kidney Donation with Realistic Incentives

Treatment for end-stage renal (kidney) disease (ESRD) is the only government-funded health care in the United States that has no financial need- or age-based criteria; inclusion in the program (Medicare) is solely based on diagnosis. If a person has ESRD, treatment is covered by Medicare. No other criteria must be met, but the best treatment option, a transplant, is not available for most patients. Compared with dialysis, a kidney transplant significantly prolongs life and improves quality of life, but kidneys are scarce in large part because federal law prohibits the buying and selling of organs. The average waiting time for a kidney transplant in the United States approaches 5 years; in some parts of the country, it is closer to 10 years. A significant number of transplant candidates die while waiting for an altruistic donation that never comes. Allowing the sale of kidneys from living donors would greatly increase the supply of kidneys and thereby save lives and minimize the number of patients suffering on dialysis. The National Organ Transplant Act of 1984 was passed to, among other things, prohibit the sale of organs in the face of apprehension that the growing commercialization of medicine would result in human beings being treated as commodities rather than individuals. Whether such concerns were well founded or not, the act was clearly overbroad in its prohibition of the sale of organs. It's time to loosen those restrictions in order to save lives. The best way to increase the supply of kidneys without drastically changing the existing allocation system is to legalize a regulated system of compensation for living kidney donors. Such a system could be established using the infrastructure already in place for evaluating deceased donors and allocating their organs. The only change required to ease and probably even solve the organ shortage is some form of payment for donors. The potential practical and theoretical concerns with compensated donation can be overcome, and alternative proposals will not do enough to solve the shortage. Upon careful analysis, it is clear that the benefits of a regulated system of compensated donation (chiefly, increasing the number of donated kidneys) outweigh any risks