Mirror symmetry for N=1 QED in three dimensions

We construct three-dimensional N=1 QED with N_f flavors using branes of type IIB string theory. This theory has a mirror, which can be realized using the S-dual brane configuration. As in examples with more supersymmetry, the Higgs branch of the original theory gets mapped into the Coulomb branch of the mirror. We use parity invariance to argue that these branches cannot be lifted by quantum corrections.Comment: 10 pages, Latex, 1 figure, reference adde

Interactive effects of pH, temperature and exposure period on native and invasive mussels from the West Coast of South Africa

Global warming and ocean acidification due to an increase in anthropogenic carbon dioxide can impact marine calcifying organisms. Shells of marine calcifying organisms protect their internal soft tissue and may be key in determining the susceptibility of marine calcifiers to these environmental stressors. To test this, the effects of pH, temperature, exposure period and their interactions on the performance of native and alien mussels with varying shell thickness was studied. Listed in order of decreasing shell thickness, I compared shell dissolution, shell growth, shell breaking force and condition index of Aulacomya ater, Choromytilus meridionalis (both native), Mytilus galloprovincialis and Semimytilus algosus (both invasive) found on the Western Cape coast of South Africa. Live mussels and bare shells were exposed to seawater temperatures of 14°C and 20°C set at two pH levels (7.5 and 8.0) for roughly 40 days. Live mussels were either exposed to aerial drying for four hours per day or fully submerged for the duration of the study. The results suggest that shell thickness determines the susceptibility of mussels to environmental stressors, in terms of shell dissolution and breaking force, but does not affect internal growth. Invasive mussels showed increased shell dissolution at low pH but their growth rates were unaffected. They also exhibited higher condition indices than native mussels under low pH and high temperatures. On the other hand, the thicker shelled native mussels showed no significant changes in shell dissolution among the treatments and exhibited increases in growth rates in low pH treatments. C. meridionalis, being cold water adapted, exhibited a reduction in condition index in high temperature treatments. The study indicates that native and invasive mussels have different compensatory mechanisms to respond to anthropogenic impacts. These mechanisms allow them to maintain their specific life history strategies under short term exposure to warming and acidification. It was also elucidated that mussels exposed to low temperature aerial conditions exhibit increased shell and tissue growth as periodic exposure minimises the deleterious effects of ocean acidification and warming. The findings suggest that native and invasive mussels respond differently to ocean acidification and warming depending on their specific physiologies and life history strategies

Automata Tutor v3

Computer science class enrollments have rapidly risen in the past decade. With current class sizes, standard approaches to grading and providing personalized feedback are no longer possible and new techniques become both feasible and necessary. In this paper, we present the third version of Automata Tutor, a tool for helping teachers and students in large courses on automata and formal languages. The second version of Automata Tutor supported automatic grading and feedback for finite-automata constructions and has already been used by thousands of users in dozens of countries. This new version of Automata Tutor supports automated grading and feedback generation for a greatly extended variety of new problems, including problems that ask students to create regular expressions, context-free grammars, pushdown automata and Turing machines corresponding to a given description, and problems about converting between equivalent models - e.g., from regular expressions to nondeterministic finite automata. Moreover, for several problems, this new version also enables teachers and students to automatically generate new problem instances. We also present the results of a survey run on a class of 950 students, which shows very positive results about the usability and usefulness of the tool

Free trade agreements and the consolidation of democracy

We study the relationship between participation in free trade agreements (FTAs) and the sustainability of democracy. Our model shows that FTAs can critically reduce the incentive of authoritarian groups to seek power by destroying protectionist rents, thus making democracies last longer. This gives governments in unstable democracies an extra motive to form FTAs. Hence, greater democratic instability induces governments to boost their FTA commitments. In a dataset with 116 countries over 1960-2007, we find robust support for these predictions. They help to rationalize the rapid simultaneous growth of regionalism and of worldwide democratization since the late 1980s

Charged Less, Paid More - Non-optimal Tariff Choice Decisions in the Electric Vehicle Services Market

Electric vehicle users need to subscribe to an Electric Mobility Platform Service provider to gain access to public charging networks. Consequently, consumers need to form beliefs about their future demand for the (charging) service in order to choose a tariff that maximizes their surplus. Using a unique dataset from a large Western European Electric Mobility Platform Service provider, we show that a significant share of customers conducts systematic tariff-choice errors. We find that customers of two-part tariffs are more likely to choose a non-optimal tariff than customers of a pay-per-use tariff. Additionally, the likelihood of a non-optimal pay-per-use tariff choice depends on the user’s type of plug-in electric vehicle. We explain the non-optimal tariff choices by cognitive biases related to reference dependence and overconfidence. We further outline our next steps to better understand non-optimal choice behavior in the electric vehicle services market and provide implications for managers and policymakers

Pay today, or delay the pay: Consumer preference for double flat-rate pricing plans

Double flat-rate pricing plans are a pricing strategy used in a variety of industries, including digital add-on services for durable products. These pricing plans consist of two distinct components: a nonrecurring flat rate and a recurring flat rate. A nonrecurring flat rate consists of a one-time, initial, nonrecurring provisioning fee. A recurring flat rate is a recurring (usually monthly) subscription fee that entitles consumers to unlimited access to the service without additional usage-based charges. While previous research has extensively studied single flat-rate pricing plans, consumer preference for double flat-rate pricing plans compared to single flat-rate plans has not yet been studied. We conduct two discrete choice experiments for utilitarian products in different industries and find that—contrary to the increasing use of double flat-rate pricing plans—consumers tend to prefer single flat-rate plans. Moreover, we find substantial preference heterogeneity for the two pricing plan components. Nonrecurring flat-rate fees have a greater influence on consumer choice than recurring flat-rate fees. We discuss the theoretical implications for behavioral pricing and consumers’ tariff choice decisions, as well as the managerial implications for firms’ pricing menu decisions

The 3.3 micron emission feature: Map of the galactic disk, 10 deg less than 1 less than 35 deg, - 6 deg less than b less than 6 deg

The 3.3 micron aromatic feature has been detected in the diffuse galactic emission with the AROME balloon-borne instrument. The results are presented in the form of an map of the 3.3 micron feature's intensity. The AROME instrument consists in a Cassegrain telescope with wobbling secondary mirrors and a liquid/solid nitrogen cooled photometer. The instrumental output is modified by the impulse response of the system. So the galactic surface brightness was restored in Fourier space by an inverse optimal filtering. The map of the feature's intensity is presented for a region of galactic coordinates. All the known H II giant molecular cloud complexes are visible in the 3.3 micron feature emission showing a good correlation with the infrared dust emission

Evaluating geospatial context information for travel mode detection

Detecting travel modes from global navigation satellite system (GNSS) trajectories is essential for understanding individual travel behavior and a prerequisite for achieving sustainable transport systems. While studies have acknowledged the benefits of incorporating geospatial context information into travel mode detection models, few have summarized context modeling approaches and analyzed the significance of these context features, hindering the development of an efficient model. Here, we identify context representations from related work and propose an analytical pipeline to assess the contribution of geospatial context information for travel mode detection based on a random forest model and the SHapley Additive exPlanation (SHAP) method. Through experiments on a large-scale GNSS tracking dataset, we report that features describing relationships with infrastructure networks, such as the distance to the railway or road network, significantly contribute to the model's prediction. Moreover, features related to the geospatial point entities help identify public transport travel, but most land-use and land-cover features barely contribute to the task. We finally reveal that geospatial contexts have distinct contributions in identifying different travel modes, providing insights into selecting appropriate context information and modeling approaches. The results from this study enhance our understanding of the relationship between movement and geospatial context and guide the implementation of effective and efficient transport mode detection models.Comment: updated Method and Discussion; accepted by Journal of Transport Geograph