Random Feature Maps via a Layered Random Projection (LaRP) Framework for Object Classification

The approximation of nonlinear kernels via linear feature maps has recently gained interest due to their applications in reducing the training and testing time of kernel-based learning algorithms. Current random projection methods avoid the curse of dimensionality by embedding the nonlinear feature space into a low dimensional Euclidean space to create nonlinear kernels. We introduce a Layered Random Projection (LaRP) framework, where we model the linear kernels and nonlinearity separately for increased training efficiency. The proposed LaRP framework was assessed using the MNIST hand-written digits database and the COIL-100 object database, and showed notable improvement in object classification performance relative to other state-of-the-art random projection methods.Comment: 5 page

The influence of the cluster environment on the star formation efficiency of 12 Virgo spiral galaxies

The influence of the environment on gas surface density and star formation efficiency of cluster spiral galaxies is investigated. We extend previous work on radial profiles by a pixel-to pixel analysis looking for asymmetries due to environmental interactions. The star formation rate is derived from GALEX UV and Spitzer total infrared data. As in field galaxies, the star formation rate for most Virgo galaxies is approximately proportional to the molecular gas mass. Except for NGC 4438, the cluster environment does not affect the star formation efficiency with respect to the molecular gas. Gas truncation is not associated with major changes in the total gas surface density distribution of the inner disk of Virgo spiral galaxies. In three galaxies, possible increases in the molecular fraction and the star formation efficiency with respect to the total gas, of factors of 1.5 to 2, are observed on the windward side of the galactic disk. A significant increase of the star formation efficiency with respect to the molecular gas content on the windward side of ram pressure-stripped galaxies is not observed. The ram-pressure stripped extraplanar gas of 3 highly inclined spiral galaxies shows a depressed star formation efficiency with respect to the total gas, and one of them (NGC 4438) shows a depressed rate even with respect to the molecular gas. The interpretation is that stripped gas loses the gravitational confinement and associated pressure of the galactic disk, and the gas flow is diverging, so the gas density decreases and the star formation rate drops. However, the stripped extraplanar gas in one highly inclined galaxy (NGC 4569) shows a normal star formation efficiency with respect to the total gas. We propose this galaxy is different because it is observed long after peak pressure, and its extraplanar gas is now in a converging flow as it resettles back into the disk.Comment: 34 pages, 24 figures, accepted for publication by A&

Socioeconomic Patterns of COVID-19 Clusters in Low-Incidence City, Hong Kong

Although coronavirus disease (COVID-19) outbreaks have been relatively well controlled in Hong Kong, containment remains challenging among socioeconomically disadvantaged persons. They are at higher risk for widespread COVID-19 transmission through sizable clustering, probably because of exposure to social settings in which existing mitigation policies had differential socioeconomic effects

COVID-19 related health inequality exists even in a city where disease incidence is relatively low: a telephone survey in Hong Kong

Background: We examined whether COVID-19 could exert inequalities in socioeconomic conditions and health in Hong Kong, where there has been a relatively low COVID-19 incidence. Methods: 752 adult respondents from a previous random sample participated in a telephone survey from 20 April to 11 May 2020. We examined demographic and socioeconomic factors, worry of COVID-19, general health, economic activity, and personal protective equipment (PPE) and related hygiene practice by deprivation status. The associations between deprivation and negative COVID-19 related issues were analysed using binary logistic regressions, while the associations of these issues with health were analysed using linear regressions. Path analysis was conducted to determine the direct effect of deprivation, and the indirect effects via COVID-19 related issues, on health. Interactions between deprivation and the mediators were also tested. Results: Deprived individuals were more likely to have job loss/instability, less reserves, less utilisation and more concerns of PPE. After adjustments for potential confounders, being deprived was associated with having greater risk of low reserve of face masks, being worried about the disease and job loss/instability. Being deprived had worse physical (β=−0.154, p<0.001) and mental health (β=−0.211, p<0.001) and had an indirect effect on mental health via worry and job loss/instability (total indirect effect: β=−0.027, p=0.017; proportion being mediated=11.46%). In addition, significant interaction between deprivation and change of economic activity status was observed on mental health-related quality of life. Conclusion: Even if the COVID-19 incidence was relatively low, part of the observed health inequality can be explained by people’s concerns over livelihood and economic activity, which were affected by the containment measures. We should look beyond the incidence to address COVID-19 related health inequalities

Experience of South and Southeast Asian minority women in Hong Kong during COVID-19 pandemic: a qualitative study

BACKGROUND: Hong Kong has a relatively low incidence rate of COVID-19 across the globe. Nevertheless, ethnic minorities in Hong Kong, especially South Asians (SAs) and Southeast Asians (SEAs), face numerous physical, mental, social, economic, cultural and religious challenges during the pandemic. This study explores the experiences of SA and SEA women in a predominantly Chinese metropolitan city. METHODS: Ten SA and SEA women were recruited and face-to-face interviews were conducted. Questions about participants’ daily life experience, physical and mental health conditions, economic situation and social interaction amid COVID-19 pandemic were asked to assess the impact of COVID-19. RESULTS: SAs and SEAs have a distinctive family culture, and women experienced significant physical and mental impact of COVID-19 due to their unique gender role in the family. In addition to taking care of their family in Hong Kong, SA and SEA women also had to mentally and financially support family members residing in their home countries. Access to COVID-related information was restricted due to language barrier. Public health measures including social distancing imposed extra burden on ethnic minorities with limited social and religious support. CONCLUSIONS: Even when COVID-19 incidence rate is relatively low in Hong Kong, the pandemic made life even more challenging for SAs and SEAs, which is a community already struggling with language barriers, financial woes, and discrimination. This in turn could have led to greater health inequalities. Government and civil organizations should take the social determinants of health inequalities into account when implementing COVID-19-related public health policies and strategies

Secular trends of life expectancy and disability-free life expectancy at age 65 and associated gender and area-level socioeconomic inequalities in Hong Kong: a serial cross-sectional study between 2007 and 2020

BACKGROUND: Despite Hong Kong's world leading longevity, little is known about its associated disability burden and social patterning. Hence, this study assessed the gender-specific secular trends and area-level inequalities in life expectancy (LE) and disability-free life expectancy (DFLE) at age 65 in Hong Kong. METHODS: Population structure, death records, and disability data in 2007, 2013, and 2020 were retrieved from the Census and Statistics Department to estimate LE and DFLE using the Sullivan Method. District-based sociodemographic indicators were used to compare LE and DFLE across 18 districts of Hong Kong in 2013. FINDINGS: Between 2007 and 2020, LE at age 65 increased by 3.7 years (from 18.3 to 22.0) in men and by 2.1 years (from 22.7 to 24.8) in women. By contrast, DFLE increased more slowly, by 1.8 years (from 14.6 to 16.3) in men and by only 0.1 year (from 16.4 to 16.5) in women, leading to a substantial increase in proportion of life spent with disability. Results from multiple linear regression using district-based data in 2013 showed a similar extent of associations of education with LE and DFLE (mean year difference: 0.81 [95% CI: 0.14, 1.48] and 0.68 [0.10, 1.27], respectively, per 10% increase in average education level), while female gender was more strongly associated with LE (4.44 [3.56, 5.31]) than with DFLE (2.00 [1.18, 2.82]). INTERPRETATION: Expansion of disability burden and male-female health-survival paradox hold true in Hong Kong. Unlike Western countries with a stronger socioeconomic patterning of DFLE, the extent of area-level socioeconomic inequalities in LE and DFLE appears to be more comparable in Hong Kong. FUNDING: Health and Medical Research Fund (Ref. no.: 19202031) by the Health Bureau of Hong Kong

The mediating role of individual-level social capital among worries, mental health and subjective well-being among adults in Hong Kong during the COVID-19 pandemic

The COVID-19 pandemic has substantially induced worries and affected individual mental health and subjective well-being. Nonetheless, a high level of social capital could potentially protect individuals who suffer from mental health problems and thus promote their subjective well-being, especially under the social distancing policies during the pandemic. To this end, based on a random sample of 1053 Hong Kong adults, structural equation modeling was applied to study the path relationships between the worries of COVID-19, social capital, mental health problems, and subjective well-being. The study found that worries during the pandemic were associated with mental health and subjective well-being, through social capital as a mediator. Moreover, social capital exhibited a stronger influence on mental health and subjective well-being in the economically inactive group than in the economically active group. This study highlights the important role of social capital during the COVID-19 pandemic. While Hong Kong’s COVID-19 response has primarily focused on disease prevention, it must be noted that social services and mutual-help activities are also crucial for people to withstand the crisis

Socioeconomic inequality in mental well-being associated with COVID-19 containment measures in a low-incidence Asian globalized city

The COVID-19 pandemic exposes and amplifies pre-existing inequalities even in places with relatively well-controlled outbreaks such as Hong Kong. This study aimed to explore whether the socioeconomically disadvantaged fare worse via various types of worry in terms of their mental health and well-being. Between September and October 2020, 1067 adults in Hong Kong were recruited via a cross-sectional population-wide telephone survey. The inter-relationship between deprivation, types of worry, mental health disorders, and subjective well-being was assessed using structural equation modelling. Results showed significant total effects of deprivation on worries about being infected (p = 0.002), economic activities and livelihood (p < 0.001), and personal savings (p < 0.001), as well as mental health disorders (p < 0.001) and subjective well-being (p < 0.001). Specifically, worry about economic activities and livelihood partly mediated the total effect of deprivation on mental health disorders (p = 0.004), whereas worry about personal savings and worry about economic activities and livelihood partially mediated the total effect of deprivation on subjective well-being (p = 0.007 and 0.002, respectively). Socioeconomic inequality, particularly in mental health and well-being, could be exacerbated via people’s economic concerns during the pandemic, which was largely induced by the COVID-19 containment measures rather than the pandemic per se given the relatively low COVID-19 incidence in Hong Kong

Learning from the severe acute respiratory syndrome (SARS) epidemic

Author name used in this publication: Joanne W. Y. Chung2007-2008 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe