City as lens: (re)imagining youth in Glasgow and Hong Kong

In recent years, a paradox has emerged in the study of youth. On the one hand, in the context of the processes of globalization, neoliberalism and precarity, the patterning of leisure and work for young people is becoming increasingly convergent across time and space. On the other hand, it is clear that young people’s habits and dispositions remain deeply tied to local places, with global processes filtered and refracted through specific cultural contexts. Against this backdrop, drawing on an Economic and Social Research Council/Research Grants Council (ESRC/RGC)-funded study of contemporary youth in Glasgow and Hong Kong, this article seeks to explore the role of the city as a mediating lens between global forces and local impacts. Utilizing both historical and contemporary data, the article argues that despite parallels in the impact of global forces on the structure of everyday life and work, young people’s leisure habits remain rooted in the fates and fortunes of their respective cities

Topological kink states at a tilt boundary in gated multi-layer graphene

The search for new realization of topologically protected edge states is an active area of research. We show that a tilt boundary in gated multi-layer graphene supports topologically protected gapless kink states, associated with quantum valley Hall insulator (QVH). We investigate such kink states from two perspectives: the microscopic perspective of a tight-binding model and an ab-initio calculation on bilayer, and the perspective of symmetry protected topological (SPT) states for general multi-layer. We show that a AB-BA bilayer tilt boundary supports gapless kink states that are undeterred by strain concentrated at the boundary. Further, we establish the kink states as concrete examples of edge states of {\it time-reversal symmetric} ${\mathbb Z}$-type SPT, protected by no valley mixing, electron number conservation, and time reversal $T$ symmetries. This allows us to discuss possible phase transitions upon symmetry changes from the SPT perspective. Recent experimental observations of a network of such tilt boundaries suggest that transport through these novel topological kink states might explain the long standing puzzle of sub-gap conductance. Further, recent observation of gap closing and re-opening in gated bi-layer might be the first example of a transition between two distinct SPT's: QVH and LAF.Comment: Improved a discussion of the structural aspects of the tilt boundary. Included a discussion of boundary condition dependence. Added new section on connection to experiment

An Examination of the Joint Impacts of Review Content and Reviewer Characteristics on Review Usefulness—the Case of Yelp.com

We examine the interaction effects of review content (certainty) and reviewer characteristics (popularity and expertise) on consumer judgment of review usefulness. Utilizing an extended Poisson regression model, we empirically tested the joint impacts based on 5426 reviews from Yelp.com about 968 restaurants. Our results indicate that (1) reviewer popularity negatively interacts with certainty to affect review usefulness and (2) in contrast, reviewer expertise positively interacts with certainty to affect review usefulness. These findings add new insights into online review research and offer practical implications for online review platforms

An Investigation of the Presentational Impacts of User-Generated Picture and Text on Consumer Information Processing and Attitude Outcomes in the e-WOM Context

Given the importance of e-WOM and the lack of academic research on the role of pictures in influencing consumer decision making, we adapt the cue summation theory to examine the effects of the relative layout (the alternate layout vs. the separate layout) and relative sequence (UGP first vs. UGT first) on diagnosticity, pleasantness of e-WOM and customers’ attitude towards the recommended product/service in the e-WOM. We conduct an experiment to test our research model. The results show that separate layout is better than the alternate layout in perceived diagnosticity and product evaluation, especially when the UGP is displayed first than the UGT first displayed. In contrast, for pleasantness, alternate layout is better than separate layout, regardless of the sequence of text and picture. These findings make important contributions to e-WOM literature and extend cue-summation theory. Our research also provides guidelines on the presentational strategies of e-WOM

Aggregate real exchange rate persistence through the lens of sectoral data

15 páginas, 2 figuras, 3 tablas.-- El pdf es la versión pre-print del artículo.-- Trabajo presentado a la conferencia "Microeconomic Sources of Real Exchange Rates" (Vanderbilt University-USA, 2010).A novel approach to analyzing real exchange rate (RER) persistence and its sources is presented. Using highly disaggregated data for a group of EU-15 countries, it is shown that the distribution of sectoral persistence is highly heterogeneous and skewed to the right, so that a limited number of sectors are responsible for the high levels of persistence observed at the aggregate level. Quantile regression has been employed to investigate whether traditional theories, such as the lack of arbitrage due to nontradability or imperfect competition combined with price stickiness, are able to account for the slow reversion to parity of RERs.Financial support from the Spanish Government CICYT projects SEJ2006-00369 and ECO2008-03040Peer reviewe

An Experimental Study of Byzantine-Robust Aggregation Schemes in Federated Learning

Byzantine-robust federated learning aims at mitigating Byzantine failures during the federated training process, where malicious participants may upload arbitrary local updates to the central server to degrade the performance of the global model. In recent years, several robust aggregation schemes have been proposed to defend against malicious updates from Byzantine clients and improve the robustness of federated learning. These solutions were claimed to be Byzantine-robust, under certain assumptions. Other than that, new attack strategies are emerging, striving to circumvent the defense schemes. However, there is a lack of systematic comparison and empirical study thereof. In this paper, we conduct an experimental study of Byzantine-robust aggregation schemes under different attacks using two popular algorithms in federated learning, FedSGD and FedAvg . We first survey existing Byzantine attack strategies and Byzantine-robust aggregation schemes that aim to defend against Byzantine attacks. We also propose a new scheme, ClippedClustering , to enhance the robustness of a clustering-based scheme by automatically clipping the updates. Then we provide an experimental evaluation of eight aggregation schemes in the scenario of five different Byzantine attacks. Our results show that these aggregation schemes sustain relatively high accuracy in some cases but are ineffective in others. In particular, our proposed ClippedClustering successfully defends against most attacks under independent and IID local datasets. However, when the local datasets are Non-IID, the performance of all the aggregation schemes significantly decreases. With Non-IID data, some of these aggregation schemes fail even in the complete absence of Byzantine clients. We conclude that the robustness of all the aggregation schemes is limited, highlighting the need for new defense strategies, in particular for Non-IID datasets.Comment: This paper has been accepted for publication in IEEE Transactions on Big Dat

DURABILITY OF RUNNING SHOES WITH EVA AND PU MIDSOLE

Running shoes may play an important role in preventing injuries by absorbing external shock due to ground impact (Cook et al., 1990; Verdejo and Mills, 2004). Shoe age maybe an important factor in running injuries. One prospective study showed that running injury was associated with shoe age (Taunton et al., 2003). In recent years, different types of foam materials have been developed for running shoe midsoles. Two common types of foam materials, Ethylene Vinyl Acetate (EVA) and Polyurethane (PU), are now widely used in running shoe midsoles. The purpose of the present study was to examine the durability of running shoes with common types of EVA and PU midsole materials