Disrupting Personal (In)Security? The Role of Ride-Hailing Service Features, Commute Strategies, and Gender in Mexico City

This paper sheds light on the personal security dimension of ride-hailing from a gender perspective. We explore how features of Transportation Network Companies (TNCs) services affect riders perceptions of security when commuting in ride-hailing services, and how general perceptions of fear of crime shape the way people value such features. Moreover, we analyze the strategies women and men are using to enhance their own security in ride-hailing and factors influencing these strategies. We conducted a survey of users of the TNC DiDi in Mexico City. The statistical methods used are structural equation models SEM and ordered logit models OLOGIT. Results show that women are more likely to value the information made available by ride-hailing applications (e.g., knowing your location or knowing driver information) and the presence of a panic button. The value given to information also increases if a person feels insecure in the streets, in a public transit station or in public transit. People who perceive higher insecurity in the streets have increased positive perceptions of the possibility of travelling without transfers. We also find that women are 64.4% less likely to share ride-hailing trips (pooling) and 2.14 times more likely to share details of their trips through their cellphones

Ready to ride: security and transit-related determinants of ride-hailing adoption in Latin America

Previous research on ride-hailing has focused on the effects that the built environment, demographic variables, and personal attitudes have on the frequency of ride-hailing use, finding that adopters are mainly young and highly educated people with increased levels of technology embracement. Despite that some scholars have shown that the convenience of ride-hailing such as their flexibility and major geographical coverage has led to users to prefer services provided by Transportation Network Companies (TNCs) over public transportation for some trips, there is a lack of research on how perceptions of public transit systems and TNCs can induce ride-hailing usage. In this article we extend the understanding of ride-hailing phenomena by proposing that structural gaps in public transit are key explanatory variables in the uptake and willingness to pay for ride-hailing trips. Building on an international survey in Mexico City, Bogotá, and Medellín, we develop a Structural Equation Model (SEM) incorporating latent variables expressing perceptions people have about features of ride-hailing and vulnerabilities in public transit. Results show that these variables are relevant. We also confirm that educational attainment and income are instrumental for ride-hailing trips, and that technology embracement is the most important variable to distinguish among levels of adoption. Findings inform public policy by focusing on the negative experiences of using public transit and how this could be generating more ride-hailing trips. TNCs are an attractive transport alternative that can fill gaps in public transit systems but that are also benefiting from structural problems in the transit systems

Looking in the Heads of Experienced Teachers – Do they use the Wide Range of Principles of Effective Teaching when Analysing Lessons?

This study aimed to examine whether principles of effective teaching constitute essential criteria for a systematic and successful analysis of lessons. After watching a video of a complete lesson, the participants (each of nine experienced and pre-service teachers) were asked to analyse this lesson in terms of effectiveness for pupils’ learning in the form of an open dialogue. Their comments were analysed by means of a qualitative content analysis and revealed that the experienced teachers independently used the wide range of principles of effective teaching and differed significantly from the pre-service teachers in this regard. Particularly striking were the large differences in the activation of knowledge about these five principles: goal orientation, relating cognitive activities to prior knowledge, classroom climate/learning atmosphere, clarity, and using appropriate examples. These differences point to specific development tasks, in order to improve the analytical skills of student teachers within teacher education

Cities Under Lockdown: Mobility and Access Inequalities Stemming from COVID-19 in Urban Colombia

The effects of the COVID-19 pandemic on cities have transformed the lives of urban societies across the globe. One of such effects has been the redefinition of access and urban mobility patterns, exposing divides and inequalities along the lines of class, gender and social positions. In Latin America, long-term lockdowns and widespread containment-oriented restrictions have deepened already acute conditions of poverty and deprivation. Low-income and socially vulnerable households and individuals in countries such as Colombia find themselves unable, or in a disadvantaged position, to work from home, access goods and services securely and avoid transport modes that increase exposure to contagion. This chapter examines inequalities in urban mobility and access to essential opportunities in urban settings in Colombia, through data collected from 3,900 respondents to a web survey organised during the national lockdown in the country in April 2020. The chapter presents a Latent Class Analysis model exploring how intersecting differences in class, gender, ethnicity, age and other relevant socioeconomic characteristics, influence the degree of adaptability and capacity to adapt to the challenging conditions posed by COVID-19 for physical travel and carrying out everyday activities. Building on three distinct classes of mobility and access-related conditions, the chapter reflects on structural inequalities associated with Colombian cities’ urban form, functional and productive structures and its wide social gaps. The chapter builds on empirical findings to reflect on urban policy and discuss avenues for addressing social and spatial inequalities worsened by the pandemic

Die Optimierung von Medienentscheidungen in der Unterrichtsplanung – eine Utopie?

Der Beitrag zielt auf eine mediendidaktische Interpretation der Optimierungsidee und diskutiert die Verknüpfung einer kognitionspsychologischen und informationstechnologischen Sichtweise. Ausgangspunkt ist das zentrale mediendidaktische Prinzip, das besagt, dass optimale Medienentscheidungen bei mediengestützten Lernangeboten in Wechselwirkungen mit anderen Planungsbereichen stehen sollten, zum Beispiel mit den Lernvoraussetzungen, -zielen oder -inhalten. Die Konsequenz dieses Interdependenzprinzips ist, wechselwirkende Medienentscheidungen mit den weiteren Planungsentscheidungen und -voraussetzungen bereits in der Unterrichtsplanung treffen zu müssen, die zu einem möglichst stimmigen Unterrichtsentwurf führen, dessen Qualität dann im Kreislauf von Planung, Durchführung und Analyse der Lernangebote stetig weiter zu entwickeln ist. Im vorliegenden Beitrag wird dieses mediendidaktische Prinzip aufgegriffen und zunächst aus der Perspektive der Cognitive Load-Theorie gefragt, ob das Optimum einer interdependenten Unterrichtsplanung die Planenden – massgeblich Planungsnovizinnen und -novizen – kognitiv überfordert und deshalb eine Utopie bleiben muss. Anschliessend wird eine technologiebasierte Lerngelegenheit – eine Planungssoftware – vorgestellt, die das kognitiv entlastende Erlernen interdependenter Planungsentscheidungen unterstützt und einen möglichen Weg aufzeigt, das Treffen interdependenter Planungsentscheidungen selbst für Planungsnovizinnen und -novizen realistisch werden zu lassen

Benchmarking highly entangled states on a 60-atom analog quantum simulator

Quantum systems have entered a competitive regime where classical computers must make approximations to represent highly entangled quantum states. However, in this beyond-classically-exact regime, fidelity comparisons between quantum and classical systems have so far been limited to digital quantum devices, and it remains unsolved how to estimate the actual entanglement content of experiments. Here we perform fidelity benchmarking and mixed-state entanglement estimation with a 60-atom analog Rydberg quantum simulator, reaching a high entanglement entropy regime where exact classical simulation becomes impractical. Our benchmarking protocol involves extrapolation from comparisons against many approximate classical algorithms with varying entanglement limits. We then develop and demonstrate an estimator of the experimental mixed-state entanglement, finding our experiment is competitive with state-of-the-art digital quantum devices performing random circuit evolution. Finally, we compare the experimental fidelity against that achieved by various approximate classical algorithms, and find that only one, which we introduce here, is able to keep pace with the experiment on the classical hardware we employ. Our results enable a new paradigm for evaluating the performance of both analog and digital quantum devices in the beyond-classically-exact regime, and highlight the evolving divide between quantum and classical systems.Comment: ALS, ZC, and JC contributed equall

SPDZ2k: Efficient MPC mod 2^k for Dishonest Majority

Most multi-party computation protocols allow secure computation of arithmetic circuits over a finite field, such as the integers modulo a prime. In the more natural setting of integer computations modulo $2^{k}$, which are useful for simplifying implementations and applications, no solutions with active security are known unless the majority of the participants are honest. We present a new scheme for information-theoretic MACs that are homomorphic modulo $2^k$, and are as efficient as the well-known standard solutions that are homomorphic over fields. We apply this to construct an MPC protocol for dishonest majority in the preprocessing model that has efficiency comparable to the well-known SPDZ protocol (Damgård et al., CRYPTO 2012), with operations modulo $2^k$ instead of over a field. We also construct a matching preprocessing protocol based on oblivious transfer, which is in the style of the MASCOT protocol (Keller et al., CCS 2016) and almost as efficient

Realization of a density-dependent Peierls phase in a synthetic, spin-orbit coupled Rydberg system

We experimentally realize a Peierls phase in the hopping amplitude of excitations carried by Rydberg atoms, and observe the resulting characteristic chiral motion in a minimal setup of three sites. Our demonstration relies on the intrinsic spin-orbit coupling of the dipolar exchange interaction combined with time-reversal symmetry breaking by a homogeneous external magnetic field. Remarkably, the phase of the hopping amplitude between two sites strongly depends on the occupancy of the third site, thus leading to a correlated hopping associated to a density-dependent Peierls phase. We experimentally observe this density-dependent hopping and show that the excitations behave as anyonic particles with a non-trivial phase under exchange. Finally, we confirm the dependence of the Peierls phase on the geometrical arrangement of the Rydberg atoms.Comment: 10 pages, 7 figure