Collaboration or competition: The impact of incentive types on urban cycling

Bicycling is an important mode of transport for cities and many cities are interested in promoting its uptake by a larger portion of the population. Several cycling mobile applications primarily rely on competition as a motivation strategy for urban cyclists. Yet, collaboration may be equally useful to motivate and engage cyclists. The present research reports on an experiment comparing the impact of collaboration-based and competition-based rewards on users’ enjoyment, satisfaction, engagement with, and intention to cycle. It involved a total of 57 participants in three European cities: Münster (Germany), Castelló (Spain), and Valletta (Malta). Our results show participants from the study reporting higher enjoyment and engagement with cycling in the collaboration condition. However, we did not find a significant impact on the participants’ worldview when it comes to the intentions to start or increase cycling behavior. The results support the use of collaboration-based rewards in the design of game-based applications to promote urban cycling

The Functional Significance of Black-Pigmented Leaves: Photosynthesis, Photoprotection and Productivity in Ophiopogon planiscapus ‘Nigrescens’

Black pigmented leaves are common among horticultural cultivars, yet are extremely rare across natural plant populations. We hypothesised that black pigmentation would disadvantage a plant by reducing photosynthesis and therefore shoot productivity, but that this trait might also confer protective benefits by shielding chloroplasts against photo-oxidative stress. CO2 assimilation, chlorophyll a fluorescence, shoot biomass, and pigment concentrations were compared for near isogenic green- and black-leafed Ophiopogon planiscapus ‘Nigrescens’. The black leaves had lower maximum CO2 assimilation rates, higher light saturation points and higher quantum efficiencies of photosystem II (PSII) than green leaves. Under saturating light, PSII photochemistry was inactivated less and recovered more completely in the black leaves. In full sunlight, green plants branched more abundantly and accumulated shoot biomass quicker than the black plants; in the shade, productivities of the two morphs were comparable. The data indicate a light-screening, photoprotective role of foliar anthocyanins. However, limitations to photosynthetic carbon assimilation are relatively small, insufficient to explain the natural scarcity of black-leafed plants

Econometricmodel of industry, profits, and tatonnement adjustment

This study presents a quantitative analysis of one of the main forces in an economy, disaggregated short term profits, and of the process whereby the system adjusts itself to the temporary equilibrium indicated by such forces, a generalised tatonnement. Quarterly ten-equation econometric models explaining industry behaviour and profits are developed from a basic industry model for ten mutually exclusive and exhaustive industries. These models are connected with each other and with the whole by a number of linkages and by being embedded in a skeletal economy model. The system is solved at two levels. Firstly the industry models are solved individually for given values of the linking variables; the results are used to choose between alternative specifications of the models and to assess the adequacy of the formulation adopted. Secondly the whole system is solved iteratively by solving the industry models for some given trial values of the linking variables, using these solutions to derive new trial values, and repeating the process until these values converge; the results are used to assess the efficacy of the tatonnement process. The results indicate that the models proposed are good predictors of disaggregated short term profits and that the tatonnement process used produces rapid convergence to a consistent equilibrium. It is also suggested from the discrepancy between the tatonnement (quasi-competitive) and actual (imperfectly competitive) solutions that the capitalist system is inefficient in that it produces too much

The Weaponization of Poverty: An Investigation Into United States Military Recruitment Practices In High Schools Of Low-Income Communities In The Inland Empire

Military recruitment in the United States is a highly contentious subject that has yielded a multitude of prior research across a variety of academic concentrations. To further the conversation, I narrow my focus to Southern California’s Inland Empire (IE) to explore practices of military recruitment in high schools that serve students in low-income communities. I begin with a general overview of life and labor in the Inland Empire before moving into prior research on military recruitment. My empirical research consists of five in-depth interviews documenting the lived experiences of individuals hailing from and attending high school in low-income communities of the Inland Empire. Conclusions are drawn affirming the presence of targeted military recruitment in low-income high schools of the IE through participation in the Junior Reserve Officers’ Training Corps (JROTC), as well as resulting from educational policy that has disproportionately restricted academic curriculum in low-income schools. My analysis further explores connections between labor and military recruitment in the IE before concluding with discussions as to how the military strategically utilizes the cultural structure of the IE to target recruits on a personal level

Income taxes as reciprocal tariffs

Tariff ; Taxation

Income taxes as reciprocal tariffs

This article shows the equivalence between tariffs on international trade and income taxation. Traditionally, income taxes have been seen as lowering society's output through the household's labor-leisure trade-off. Income taxes also reduce the degree to which individuals specialize in market activity, which is similar to the way countries respond to tariffs in international trade. Income taxes discourage individuals from specializing in activities that reflect their comparative advantage. In so doing, income taxes may have their most distorting effects, not by encouraging individuals to work less but by causing them to spend more time working at endeavors for which their talent is limited. Using a general model of interpersonal exchange, the authors demonstrate parallels between income taxes and tariffs. Over a range of income taxes, raising taxes can benefit large groups of similarly skilled individuals and hurt small groups. As in tariff theory, the costs of income taxes are small only if they succeed in raising revenue. Thus, it is very costly for an economy to be on the downward portion of its tax revenue (Laffer) curve. The more heterogeneous the society, the higher the income tax rate that will maximize tax revenues. By overlooking the effects of heterogeneity in the workforce and the potential for workers to flee to home production, policymakers may under- or overestimate the effects of income taxes on various sectors of the economy and tax with unintended consequences.Income tax ; Tariff ; Taxation

Complementary algorithms for graphs and percolation

A pair of complementary algorithms are presented. One of the pair is a fast method for connecting graphs with an edge. The other is a fast method for removing edges from a graph. Both algorithms employ the same tree based graph representation and so, in concert, can arbitrarily modify any graph. Since the clusters of a percolation model may be described as simple connected graphs, an efficient Monte Carlo scheme can be constructed that uses the algorithms to sweep the occupation probability back and forth between two turning points. This approach concentrates computational sampling time within a region of interest. A high precision value of pc = 0.59274603(9) was thus obtained, by Mersenne twister, for the two dimensional square site percolation threshold.Comment: 5 pages, 3 figures, poster version presented at statphys23 (2007

Three New Cool Brown Dwarfs Discovered with the Wide-field Infrared Survey Explorer (WISE) and an Improved Spectrum of the Y0 Dwarf WISE J041022.71+150248.4

As part of a larger search of Wide-field Infrared Survey Explorer (WISE) data for cool brown dwarfs with effective temperatures less than 1000 K, we present the discovery of three new cool brown dwarfs with spectral types later than T7. Using low-resolution, near-infrared spectra obtained with the NASA Infrared Telescope Facility and the Hubble Space Telescope we derive spectral types of T9.5 for WISE J094305.98+360723.5, T8 for WISE J200050.19+362950.1, and Y0: for WISE J220905.73+271143.9. The identification of WISE J220905.73+271143.9 as a Y dwarf brings the total number of spectroscopically confirmed Y dwarfs to seventeen. In addition, we present an improved spectrum (i.e. higher signal-to-noise ratio) of the Y0 dwarf WISE J041022.71+150248.4 that confirms the Cushing et al. classification of Y0. Spectrophotometric distance estimates place all three new brown dwarfs at distances less than 12 pc, with WISE J200050.19+362950.1 lying at a distance of only 3.9-8.0 pc. Finally, we note that brown dwarfs like WISE J200050.19+362950.1 that lie in or near the Galactic plane offer an exciting opportunity to measure their mass via astrometric microlensing.Comment: Accepted for publication in the Astronomical Journa