Partnerships in Urban Mobility: Incentive Mechanisms for Improving Public Transit Adoption

Problem definition: Because of a prolonged decline in public transit ridership over the last decade, transit agencies across the United States are in financial crisis. To entice commuters to travel by public transit instead of driving personal vehicles, municipal governments must address the “last-mile” problem by providing convenient and affordable transportation between a commuter’s home and a transit station. This challenge raises an important question: Is there a cost-effective mechanism that can improve public transit adoption by solving the last-mile problem? Academic/practical relevance: In this paper, we present and analyze two incentive mechanisms for increasing commuter adoption of public transit. In a direct mechanism, the government provides a subsidy to commuters who adopt a “mixed mode,” which involves combining public transit with hailing rides to/from a transit station. The government funds the subsidy by imposing congestion fees on personal vehicles entering the city center. In an indirect mechanism, instead of levying congestion fees, the government secures funding for the subsidy from the private sector. We examine the implications of both mechanisms on relevant stakeholders. These two mechanisms are especially relevant because several jurisdictions in the United States have begun piloting incentive programs, in which commuters receive subsidies for ride-hailing trips that begin or end at a transit station. Methodology: We present a game-theoretic model to capture the strategic interactions among five self-interested stakeholders (commuters, public transit agency, ride-hailing platform, municipal government, and local private enterprises). Results: By examining equilibrium outcomes, we obtain three key findings. First, we characterize how the optimal interventions associated with the direct or the indirect mechanism depend on: (a) the coverage level of the public transit network; (b) the public transit adoption target; and (c) the relative strength of commuter preferences between driving and taking public transit. Second, we show that the direct mechanism cannot be budget-neutral without undermining commuter welfare. However, when the public transit adoption target is not too aggressive, we find that the indirect mechanism can increase both commuter welfare and sales to the private-sector partner while remaining budget-neutral. Finally, we show that, although the indirect mechanism restricts the scope of government intervention (by eliminating the congestion fee), it can dominate the direct mechanism by leaving all stakeholders better off, especially when the adoption target is modest. Managerial implications: Our findings offer cost-effective prescriptions for improving urban mobility and public transit ridership.

FORMATION OF A CLOSED CRANIOCEREBRAL INJURY ACCORDING TO AN INDIRECT MECHANISM: A CASE FROM EXPERT PRACTICE.

Background. Of the 600 thousand people who have received a head injury, about 50 thousand die (i.e. about 10%). There are examples in the literature that, in some cases, damage to the brain and its membranes in closed craniocerebral trauma can be formed by an indirect mechanism without direct contact of blunt solid objects with the head, which is characteristic of impulse trauma. Case presentation: in our practice, we encountered an unusual case of an indirect closed craniocerebral trauma with a fatal outcome resulting from a road traffic accident. During the forensic medical examination of the corpse, it be established that the traumatic brain injury that formed without direct contact of blunt solid objects with the head. The formation of a traumatic brain injury by the impulse mechanism is rare in forensic medical practice, therefore, each case of such an injury is of certain interest, both in practical and scientific terms. Conclusion: the impulse mechanism of head trauma, combined with the shock mechanism in road traffic accidents, is much more common than is currently believed. The source of bleeding in such cases is often the venous vessels of the cerebral hemispheres, which flow into the sagittal sinus of the dura mater.

Propaganda, Presumed Influence, and Collective Protest

Political propaganda can reduce citizens’ inclinations to protest by directly influencing their preferences or beliefs about the government. However, given that protest is risky in authoritarian societies and requires collective participation, propaganda can also reduce citizens’ inclination to protest by making them think that other citizens, rather than themselves, may have been influenced by propaganda and are, as a result, unwilling to protest. We test this indirect mechanism of propaganda using a survey experiment with Chinese internet users from diverse backgrounds and find that they do believe propaganda affects other citizens’ support for and beliefs about the government more than their own support and beliefs. Moreover, they believe that propaganda reduces other citizens’ willingness to protest, which in turn reduces their own willingness to protest. Therefore, the power of propaganda may sometimes lie more in the social perceptions and uncertainty it creates than in its direct individual effects.

Does Blast Exposure to the Torso Cause a Blood Surge to the Brain?

The interaction of explosion-induced blast waves with the torso is suspected to contribute to brain injury. In this indirect mechanism, the wave-torso interaction is assumed to generate a blood surge, which ultimately reaches and damages the brain. However, this hypothesis has not been comprehensively and systematically investigated, and the potential role, if any, of the indirect mechanism in causing brain injury remains unclear. In this interdisciplinary study, we performed experiments and developed mathematical models to address this knowledge gap. First, we conducted blast-wave exposures of Sprague-Dawley rats in a shock tube at incident overpressures of 70 and 130 kPa, where we measured carotid-artery and brain pressures while limiting exposure to the torso. Then, we developed three-dimensional (3-D) fluid-structure interaction (FSI) models of the neck and cerebral vasculature and, using the measured carotid-artery pressures, performed simulations to predict mass flow rates and wall shear stresses in the cerebral vasculature. Finally, we developed a 3-D finite element (FE) model of the brain and used the FSI-computed vasculature pressures to drive the FE model to quantify the blast-exposure effects in the brain tissue. The measurements from the torso-only exposure experiments revealed marginal increases in the peak carotid-artery overpressures (from 13.1 to 28.9 kPa). Yet, relative to the blast-free, normotensive condition, the FSI simulations for the blast exposures predicted increases in the peak mass flow rate of up to 255% at the base of the brain and increases in the wall shear stress of up to 289% on the cerebral vasculature. In contrast, our simulations suggest that the effect of the indirect mechanism on the brain-tissue-strain response is negligible (<1%). In summary, our analyses show that the indirect mechanism causes a sudden and abundant stream of blood to rapidly propagate from the torso through the neck to the cerebral vasculature. This blood surge causes a considerable increase in the wall shear stresses in the brain vasculature network, which may lead to functional and structural effects on the cerebral veins and arteries, ultimately leading to vascular pathology. In contrast, our findings do not support the notion of strain-induced brain-tissue damage due to the indirect mechanism.

Novel mechanism for primordial perturbations in minimal extensions of the Standard Model

We demonstrate that light spectator fields in their equilibrium can source sizeable CMB anisotropies through modulated reheating even in the absence of direct couplings to the inflaton. The effect arises when the phase space of the inflaton decay is modulated by the spectator which generates masses for the decay products. We call the mechanism indirect modulation and using the stochastic eigenvalue expansion show that it can source perturbations even four orders of magnitude larger than the observed amplitude. Importantly, the indirect mechanism is present in the Standard Model extended with right- handed neutrinos. For a minimally coupled Higgs boson this leads to a novel lower bound on the quartic coupling and constrains the neutrino Yukawas below unity.

Gastrointestinal Coinfection Promotes Chlamydial Pathogenicity in the Genital Tract

ABSTRACT Sexually transmitted Chlamydia, which can cause fibrotic pathology in women’s genital tracts, is also frequently detected in the gastrointestinal tract. However, the medical significance of the gastrointestinal Chlamydia remains unclear. A murine Chlamydia readily spreads from the mouse genital tract to the gastrointestinal tract while inducing oviduct fibrotic blockage or hydrosalpinx. We previously proposed a two-hit model in which the mouse gastrointestinal Chlamydia might induce the second hit to promote genital tract pathology, and we are now providing experimental evidence for testing the hypothesis. First, chlamydial mutants that are attenuated in inducing hydrosalpinx in the genital tract also reduce their colonization in the gastrointestinal tract, leading to a better correlation of chlamydial induction of hydrosalpinx with chlamydial colonization in the gastrointestinal tract than in the genital tract. Second, intragastric coinoculation with a wild-type Chlamydia rescued an attenuated Chlamydia mutant to induce hydrosalpinx, while the chlamydial mutant infection in the genital tract alone was unable to induce any significant hydrosalpinx. Finally, the coinoculated gastrointestinal Chlamydia failed to directly spread to the genital tract lumen, suggesting that gastrointestinal Chlamydia may promote genital pathology via an indirect mechanism. Thus, we have demonstrated a significant role of gastrointestinal Chlamydia in promoting pathology in the genital tract possibly via an indirect mechanism. This study provides a novel direction/dimension for further investigating chlamydial pathogenic mechanisms.

Paradoxical Autonomy in Japan’s Platform Economy

Crowdsourcing firms, their client firms and the government in Japan have advocated that crowd work provides opportunities for workers to enjoy autonomous working practices, enabling subpopulations such as women and the elderly who would otherwise be excluded from the labour market to find employment. This is far from the case. Instead, crowdsourcing is perhaps better considered a means, enabled by technological advances, by which to flexibilise the labour market. We have been witnessing a shift in the forms of domination and control imposed on labour from a direct, physical and onsite type of control to an indirect mechanism of domination that has rendered workers less visible while suppressing wages. This further implies that the paradoxical autonomy of crowd work is embedded in contemporary antagonism in Japanese employment relations.