Surface damage from perpendicular and oblique bullet impacts in stone

Controlled experiments were conducted to investigate the surface damage caused by perpendicular and oblique impacts of bullets into sandstone and limestone targets. Individual bullets fired in conditions simulating modern rifles at typical combat distances excavated craters with diameters from 22 to 74 mm and depths from 4 to 24 mm. Limestone target craters were up to twice as large and deep as those in sandstone. These craters have a complex shape consisting of a central excavation surrounded by a shallow dish, compared to the simple bowl shape of most sandstone impacts. Radial fractures extending to the edge of the target block were common in limestone targets. Impacts at an angle of 45° to the surface in both rock types result in asymmetric craters. Two common types of ammunition were compared: the steel-tipped NATO projectile generally produced larger and deeper craters than the projectile that is commonly fired from AK-47 rifles, despite having approximately half the mass of the latter. These results characterise the sort of damage that can be expected at many sites of cultural significance involved in contemporary conflict zones, and have important implications for their conservation.

Characteristics of merging behavior in large crowds

Merging pedestrian flow can be observed often at public intersections and locations where two or more channels merge. Because of restrictions on the flow, pedestrian congestion, or even crowd disasters (e.g. Hajj crush 2015) happen easily at these junctions. However, studies on merging behaviors in large crowds remain rare. This paper investigates the merging characteristics of the pedestrian flow with controlled experiments under laboratory conditions. The formation of lanes is observed, and the lane separation width can vary for different density levels. Shannon entropy is used to analyze the utilization of the passage. The space usage in the merging area is most efficient when the width of the two branches is half that of the main corridor. Furthermore, the branch and main channel can mutually bottleneck each other in the large crowds and the flowrates for the upstream, downstream and branches are investigated. This study uses spatiotemporal diagrams to explore the clogging propagation of the merging flow as well as the relationship of the velocity and position. The results can be used as references for the design of public infrastructure and human safety management.

Effectiveness of a Theory-Informed Documentary to Reduce Consumption of Meat and Animal Products: Three Randomized Controlled Experiments

Several societal issues could be mitigated by reducing global consumption of meat and animal products (MAP). In three randomized, controlled experiments (n=217 to 574), we evaluated the effects of a documentary that presents health, environmental, and animal welfare motivations for reducing MAP consumption. Study 1 assessed the documentary’s effectiveness at reducing reported MAP consumption after 12 days. This study used methodological innovations to minimize social desirability bias, a widespread limitation of past research. Study 2 investigated discrepancies between the results of Study 1 and those of previous studies by further examining the role of social desirability bias. Study 3 assessed the documentary’s effectiveness in a new population anticipated to be more responsive and upon enhancing the intervention content. We found that the documentary did not decrease reported MAP consumption when potential social desirability bias was minimized (Studies 1 and 3). The documentary also did not affect consumption among participants whose demographics suggested they might be more receptive (Study 3). However, the documentary did substantially increase intentions to reduce consumption, consistent with past studies (Studies 2 and 3). Overall, we conclude that some past studies of similar interventions may have overestimated effects due to methodological biases. Novel intervention strategies to reduce MAP consumption may be needed.

The Legitimization Effect of Crowdfunding Success: A Consumer Perspective

Based on legitimacy and consumer inference theory, we examine when, how, and why past crowdfunding success influences the perceptions and behaviors of consumers. Across five studies (four controlled experiments and one field experiment), our findings demonstrate that a young venture’s past crowdfunding success enhances consumers’ perceptions of its cognitive legitimacy. This “legitimization effect of crowdfunding success” leads to positive outcomes with respect to purchase intentions, brand attitudes, and consumers’ willingness to recommend young ventures to others. These effects are robust across different product categories. However, our findings also reveal that these positive effects occur exclusively for young ventures, whereas they disappear or even reverse for established ones.

Can I MOOC to Catch up? The Effects of Using an LMOOC as a Remedial Tool for EFL Students in Thailand

This study investigated the effects of supplementing a traditional EFL class with a grammar-focused LMOOC. It also investigated students’ attitudes to the LMOOC. Students taking a compulsory English course at a nursing college in Thailand were divided into two groups, a LMOOC group (n=33) and a non-LMOOC group (n=26). The LMOOC group engaged in a 4-week LMOOC as a supplement to their usual English classes. The non-LMOOC group continued with their usual English classes with no additional interventions. Final examination scores and gains since the midterm for the two groups were compared. Attitudes to the LMOOC were assessed using a questionnaire and interviews. Students in the LMOOC group experienced statistically significantly larger gains in grammar scores than the non-LMOOC group (M = 5.45, SD = 4.31, p < .001). Students reported very positive attitudes towards the LMOOC, in terms of enjoyment and perceived effectiveness. The estimated gains found in this small study were relatively modest, but our findings suggest that LMOOCs as a way to supplement in-class teaching may improve attainment and foster positive attitudes. Further controlled experiments to assess the wider applicability of our findings are needed.  

Unconventional non-Fermi liquid properties of two-channel Anderson impurities system

A theory for treating the unconventional non-Fermi liquid temperature dependence of physical quantities, such as the resistivity, in the Pr-based two-channel Anderson impurities system is developed. It is shown that their temperature dependences are essentially the same as those in the pure lattice system except for the case of extremely low concentration of Pr ions that is difficult to realize by the controlled experiments. This result is consistent with recent observations in diluted Pr-1-2-20 system Y1−xPrxIr2Zn20 (x = 0.024, 0.044, 0.085, and 0.44) reported in Yamane et al. Phys. Rev. Lett. 121, 077206 (2018), and is quite different from that in the case of single-channel Anderson impurities system in which the crossover between behaviors of the local Fermi liquid and heavy Fermi liquid occurs at around moderate concentration of impurities as observed in Ce-based heavy fermion system La1−xCexCu6.

Boundary extension is constrained by naturalistic image properties

Boundary extension (BE) is a classical memory illusion in which observers remember more of a scene than was presented. According to predictive accounts, BE reflects the integration of visual input and expectations of what is beyond the boundaries of a scene. Alternatively, according to normalization accounts, BE reflects one end of a normalization process towards the typically-experienced viewing distance of a scene, such that BE and boundary contraction (BC) are equally common. Here, we show that BE and BC depend on depth-of-field (DOF), as determined by the aperture settings on a camera. Photographs with naturalistic DOF led to the strongest BE across a large stimulus set, while BC was primarily observed for unnaturalistic DOF. The relationship between DOF and BE was confirmed in three controlled experiments that isolated DOF from co-varying factors. In line with predictive accounts, we propose that BE is strongest for scene images that resemble day-to-day visual experience.

An Active Learning Intervention Based on Evaluating Alternative Hypotheses Increases Scientific Literacy of Controlled Experiments in Introductory Biology

Scientific education provides a set of tools to make sense of a complex world by teasing out complicated cause-and-effect relationships, such as the elimination of effects of confounding factors in controlled experiments. There is evidence that depth of understanding of controlled experiments is lacking among undergraduate science students despite exposure to controlled experiments in courses.

Prediction and preview strongly affect reading times but not skipping during natural reading

In a typical text, readers look much longer at some words than at others and fixate some words multiple times, while skipping others altogether. Historically, researchers explained this variation via low-level visual or oculomotor factors, but today it is primarily explained via cognitive factors, such as how well words can be predicted from context or discerned from parafoveal preview. While the existence of these effects has been well established in experiments, the relative importance of prediction, preview and low-level factors for eye movement variation in natural reading is unclear. Here, we address this question using a deep neural network and Bayesian ideal observer to model linguistic prediction and parafoveal preview from moment to moment in natural reading (n=104, 1.5 million words). Strikingly, neither prediction nor preview was important for explaining word skipping - the vast majority of skipping was explained by a simple oculomotor model. For reading times, by contrast, we found clear but independent contributions of both prediction and preview, and effect sizes matching those from controlled experiments. Together, these results challenge dominant models of eye movements in reading by showing that linguistic prediction and parafoveal preview are not important determinants of word skipping.

Ambulatory Energy Expenditure Estimation: A Machine Learning Approach

This paper presents a machine learning approach for accurate estimation of energy expenditure using a fusion of accelerometer and heart rate sensing. To address short comings in existing off-the-shelf solutions, we designed Jog Falls, an end to end system for weight management in collaboration with physicians in India. This system is meant to enable people to accurately monitor their energy expenditure and intake and make educated tradeoffs to reach their weight goals. In this paper we describe the sensing components of Jog Falls and focus on the energy expenditure estimation algorithm. We present results from controlled experiments in the lab, as well results from a 15 participant user study over a period of 63 days. We show how our algorithm mitigates many of the issues in existing solutions and yields more accurate results.