The Escalator: A Conveyor of Hong Kong's Culture

People believe that escalators provide a moreattractive, convenient, and physically less-demandingpedestrian access from one place to another. However, itdoes not mean all of us have to like them. Escalators do not only affect our perception of speed, butthe most important concern is that this urban objectalso influences our social relationships and humancommunication. Under the transmission of this urban object, we are treated as components (a what),rather than human beings (a who). Thus, this articlediscusses how modernist thinking affects how we see thisobject and ourselves, and examines the relative worth of it, in relation to the social lossincurred in the present or future. This article alsodiscusses how its presence in many of the daily settingsof urban life affects the culture, meaning and quality of life.Requests for reprints should be addressed SIU Kin Wai Michael, School of Design, The Hong Kong Polytechnic University, Hunghom, Kowloon, Hong Kong.     

QUALITY DIFFERENCES,THIRD‐DEGREE PRICE DISCRIMINATION,AND WELFARE

We propose a model with two markets to analyze the welfare implications of price discrimination with quality differences. In each market a local firm that operates in that market only competes against a global firm that operates in both markets. Local firms produce higher‐quality goods than the global firm. If the quality levels of the local firms' products are the same, price discrimination is never welfare‐decreasing. If they differ, discrimination is welfare‐increasing if quantity increases. Because of a positive allocation effect of price discrimination, there are parameter values such that welfare increases while total output decreases with price discrimination. (JEL D43, D60)     

Households,Families and Prospective Economic Mobility in Mexico

The study analyzed poverty as a function of households’ demographic composition using a longitudinal random sample of 4268 urban and rural households that were followed-up from 2005/6 to 2009/12 in Mexico to estimate short-term changes in living conditions. Well-being was measured as the dwelling unit’s number of rooms, water source, sanitary services, garbage disposal, and fuel. Mobility paths included not poor–not poor, poor–poor, not poor–poor, and poor–not poor. Independent variables included household composition, family characteristics, residential changes, schooling, and occupation. Female headship and older adults negatively impacted poverty, whereas economic dependents may be negatively or positively associated. Fertility incentives for low-income populations are not advisable. Working-age adults contribute only if income-generating opportunities exist locally.     

Assessing Participation and Effectiveness of the Peer-Led Approach in Youth Sexual Health Education: Systematic Review and Meta-Analysis in More Developed Countries

Sexual health education for young people is crucial not only for development of norms but also for protection against vulnerabilities during this stage in life. Although several systematic reviews have examined the effectiveness of peer-led sex education, none have focused on the extent of peer participation. The purpose of this review was to evaluate peer-led sexual health education interventions in more developed countries (MDCs). Electronic and manual searches across five social science, education, and medical databases were conducted. Fifteen articles were selected in total. Most (10 of 15) studies gave low or no responsibility to peers. The majority of articles found improvements in sexual health knowledge (13 of 14) and attitudes (11 of 15) at postintervention stages. Two studies showed improved self-efficacy, and three showed behavioral changes. A preliminary synthesis of effectiveness and level of participation was done. Meta-analysis revealed a large effect on knowledge change (Hedges’ g = 0.84, 95% confidence interval [CI]: 0.43 to 1.25) and a medium effect on attitude change (Hedges’ g = 0.49, 95% CI: 0.19 to 0.80). Peer-led interventions could be a powerful tool. This review shows that this approach is effective in changing knowledge and attitudes but not behaviors. Further research and action are needed to understand optimal implementation.     

The role of woodpeckers (family: Picidae) as ecosystem engineers in urban parks: a case study in the city of Madrid (Spain)

Urban Ecosystems - Many species of the family Picidae, such as the woodpeckers, excavate the tree-cavities where they nest. Frequently the cavities are used during a single breeding season and...     

Daytime Sleepiness,Poor Sleep Quality,Eveningness Chronotype,and Common Mental Disorders Among Chilean College Students

Abstract

Objectives: To evaluate whether daytime sleepiness, poor sleep quality, and morningness and eveningness preferences are associated with common mental disorders (CMDs) among college students. Methods: A total of 963 college students completed self-administered questionnaires that collected information about sociodemographic characteristics, sleep quality characteristics, CMDs, and other lifestyle behaviors. Results: The prevalence of CMDs was 24.3% (95% confidence interval [CI] [21.5%, 27.1%]) among all students. Prevalence estimates of both excessive daytime sleepiness and poor sleep quality were higher among females (35.4% and 54.4%) than males (22.0% and 45.8%). Cigarette smoking was statistically significantly and positively associated with having CMDs (p = .034). Excessive daytime sleepiness (odds ratio [OR] = 3.65; 95% CI [2.56, 4.91]) and poor sleep quality (OR = 4.76; 95% CI [3.11, 7.29]) were associated with increased odds of CMDs. Conclusion: Given the adverse health consequences associated with both sleep disorders and CMDs, improving sleep hygiene among college students is imperative to public health.     

Robust bootstrap forecast densities for GARCH returns and volatilities

Bootstrap procedures are useful to obtain forecast densities for both returns and volatilities in the context of generalized autoregressive conditional heteroscedasticity models. In this paper, we analyse the effect of additive outliers on the finite sample properties of these bootstrap densities and show that, when obtained using maximum likelihood estimates of the parameters and standard filters for the volatilities, they are badly affected with dramatic consequences on the estimation of Value-at-Risk. We propose constructing bootstrap densities for returns and volatilities using a robust parameter estimator based on variance targeting implemented together with an adequate modification of the volatility filter. We show that the performance of the proposed procedure is adequate when compared with available robust alternatives. The results are illustrated with both simulated and real data.     

香港科技發展的經驗及其對澳門的啟示

從97年回歸至今,香港的科技有了很大的發展。香港在發展過程中所制訂的科技發展策略和科技政策都非常值得澳門學習,本文對回歸以來香港的科技政策進行了全面回顧,由此歸納出可资澳門借鑒的科技政策。     

Probabilistic Modeling—From Physics to Computing Science

It is important in computing science to estimate the number of data blocks needed to answer a query. Three different answers to this problem emerged respectively in 1975, 1977, and 1982. This article investigates the basic differences of the three models and observes that the same differences were shared a long time ago by the physicists who used different models for the behavior of elementary particles to obtain the Maxwell-Boltzmann statistics, the Bose-Einstein statistics, and the Fermi-Dirac statistics.