I See What You See! Towards Augmented Joint Visual Attention between Beginner and Instructor Surfers

Wave reading and selection are vital, yet challenging, for beginner surfers during the process of learning to surf. Built on the author's auto-ethnographical diaries, this paper reflects the reallife challenge of noticing when and where to catch the best wave. More importantly, beginner surfers often struggle to follow the instructor surfers who are instructing them with references to a particular wave or specific sections of a wave. The author uses the joint visual attention theory to provide a tentative explanation for this observed phenomenon. This paper proposes a speculative design solution of using AR and gaze-tracking-based goggles to foster joint attention on waves between beginner and instructor surfer, allowing the former to follow the instructor's directions and the latter to understand where the beginner is looking. This paper primarily aims to facilitate discussions in the sports HCI community and hopes to provide a reference to surfing literature in which beginner surfers and their learning experience lack attention

Characterizing HCI Research in China: Streams, Methodologies and Future Directions

This position paper takes the first step to attempt to present the initial characterization of HCI research in China. We discuss the current streams and methodologies of Chinese HCI research based on two well-known HCI theories: Micro/Marco-HCI and the Three Paradigms of HCI. We evaluate the discussion with a survey of Chinese publications at CHI 2019, which shows HCI research in China has less attention to Macro-HCI topics and the third paradigms of HCI (Phenomenologically situated Interaction). We then propose future HCI research directions such as paying more attention to Macro-HCI topics and third paradigm of HCI, combining research methodologies from multiple HCI paradigms, including emergent users who have less access to technology, and addressing the cultural dimensions in order to provide better technical solutions and support

Postsynaptic protein organization revealed by electron microscopy.

Neuronal synapses are key devices for transmitting and processing information in the nervous system. Synaptic plasticity, generally regarded as the cellular basis of learning and memory, involves changes of subcellular structures that take place at the nanoscale. High-resolution imaging methods, especially electron microscopy (EM), have allowed for quantitative analysis of such nanoscale structures in different types of synapses. In particular, the semi-ordered organization of neurotransmitter receptors and their interacting scaffolds in the postsynaptic density have been characterized for both excitatory and inhibitory synapses by studies using various EM techniques such as immuno-EM, electron tomography of high-pressure freezing and freeze-substituted samples, and cryo electron tomography. These techniques, in combination with new correlative approaches, will further facilitate our understanding of the molecular organization underlying diverse functions of neuronal synapses

Accumulation of Dense Core Vesicles in Hippocampal Synapses Following Chronic Inactivity.

The morphology and function of neuronal synapses are regulated by neural activity, as manifested in activity-dependent synapse maturation and various forms of synaptic plasticity. Here we employed cryo-electron tomography (cryo-ET) to visualize synaptic ultrastructure in cultured hippocampal neurons and investigated changes in subcellular features in response to chronic inactivity, a paradigm often used for the induction of homeostatic synaptic plasticity. We observed a more than 2-fold increase in the mean number of dense core vesicles (DCVs) in the presynaptic compartment of excitatory synapses and an almost 20-fold increase in the number of DCVs in the presynaptic compartment of inhibitory synapses after 2 days treatment with the voltage-gated sodium channel blocker tetrodotoxin (TTX). Short-term treatment with TTX and the N-methyl-D-aspartate receptor (NMDAR) antagonist amino-5-phosphonovaleric acid (AP5) caused a 3-fold increase in the number of DCVs within 100 nm of the active zone area in excitatory synapses but had no significant effects on the overall number of DCVs. In contrast, there were very few DCVs in the postsynaptic compartments of both synapse types under all conditions. These results are consistent with a role for presynaptic DCVs in activity-dependent synapse maturation. We speculate that these accumulated DCVs can be released upon reactivation and may contribute to homeostatic metaplasticity

Defense Expenditure and Economic Growth under External Predation

This paper develops a growth model of a country under a Hobbesian environment with international conflicts where national defense is the only way to prevent external predation. The long run growth path is determined by the equilibrium of a dynamic game with three players, the external predator, the government and the family. The equilibrium growth path has three phases, submissive equilibrium, tolerant equilibrium and full-protected equilibrium. Different defense strategies result in different growth prospects and sustainable growth will endogenously induce adjustment of defense strategies.economic growth; predate; defense expenditure

Holographic DC Conductivity for Backreacted NLED in Massive Gravity

In this work a holographic model with the charge current dual to a general nonlinear electrodynamics (NLED) is discussed in the framework of massive gravity. Massive graviton can breaks the diffeomorphism invariance in the bulk and generates momentum dissipation in the dual boundary theory. The expression of DC conductivities in a finite magnetic field are obtained, with the backreaction of NLED field on the background geometry. General transport properties in various limits are presented, and then we turn to the three of specific NLED models: the conventional Maxwell electrodynamics, the Maxwell-Chern-Simons electrodynamics, and the Born-Infeld electrodynamics, to study the parameter-dependence of in-plane resistivity. Two mechanisms leading to the Mott-insulating behaviors and negative magneto-resistivity are revealed at zero temperature, and the role played by the massive gravity coupling parameters are discussed.Comment: 29 pages, 13 figure