香港大学学术库——机构知识库的应用扩展

香港大学学术库是香港大学的机构知识库,是响应大学知识交流政策而建立的知识管理系统。凭借丰富的数据来源以及合理的设计机制,学术库已成为颇具影响力的香港大学人才和科研成果的展示平台,成为校内外学术交流的中心,为学术评估和声誉管理提供了基础。     

The microfluidics of the eccrine sweat gland,including biomarker partitioning,transport, and biosensing implications

Non-invasive and accurate access of biomarkers remains a holy grail of the biomedical community. Human eccrine sweat is a surprisingly biomarker-rich fluid which is gaining increasing attention. This is especially true in applications of continuous bio-monitoring where other biofluids prove more challenging, if not impossible. However, much confusion on the topic exists as the microfluidics of the eccrine sweat gland has never been comprehensively presented and models of biomarker partitioning into sweat are either underdeveloped and/or highly scattered across literature. Reported here are microfluidic models for eccrine sweat generation and flow which are coupled with review of blood-to-sweat biomarker partition pathways, therefore providing insights such as how biomarker concentration changes with sweat flow rate. Additionally, it is shown that both flow rate and biomarker diffusion determine the effective sampling rate of biomarkers at the skin surface (chronological resolution). The discussion covers a broad class of biomarkers including ions (Na⁺, Cl⁻, K⁺, NH₄⁺), small molecules (ethanol, cortisol, urea, and lactate), and even peptides or small proteins (neuropeptides and cytokines). The models are not meant to be exhaustive for all biomarkers, yet collectively serve as a foundational guide for further development of sweat-based diagnostics and for those beginning exploration of new biomarker opportunities in sweat.     

Still Playing Together(?): A Recall to Physical Education and Sport History Intersections

As academic disciplines, Physical Education and Sport History share interests in performance, participation, physique and the politics of corporeal praxis. Engendering unity between the two disciplines, however, has not been without concern. Scholars working within (and across) both fields have highlighted how the potential for shared knowledge production and meaning making has been, to a degree, stymied by epistemological and methodological criticism and trepidation. Issues over contextualization, rigour, narrative schemas, conceptualizations of the body, and notions of agency and power still, in particular, constrain our current educational and historical readings and renderings of physical culture(s). Scholarly schisms and methodological differences can be overcome, however, and need not prohibit disciplinary collaborations that might better address prevailing ethical questions and affect political cause; vis-à-vis the body, the physical and sport. This brief piece is, consequently, recourse to the scholarly symbiosis between Physical Education and Sport History and echoes the encouragement of our earlier colleagues to play, inquire, create and produce together.     

Learning outside the laboratory: Ability and non-ability influences on acquiring political knowledge

The purpose of this study was to identify sources of individual differences in knowledge acquired under natural conditions. Through its direct influence on background knowledge, crystallized intelligence (Gc) had a major impact on political knowledge, acquired over a period of more than 2 months, but there were independent influences of personality and interest factors, via exposure to political information through activities like reading the newspaper. We also found sex differences in political knowledge, favoring males, and these differences could not be explained in terms of any of the predictor variables we modeled. We discuss theoretical and practical implications of the results.     

Lifestyle, body composition, and physical fitness changes in Hungarian school boys (1975-2005)

General socioeconomic conditions as well as the physical environment have undergone remarkable changes in Hungary during the past 30 years. Unfortunately, these positive processes have resulted in a reduction of habitual physical activity along with unfavorable changes in dietary habits. Therefore, the purpose of the present study was to compare some selected morphological and functional parameters of 7-14-year-old Hungarian schoolboys living in the middle of the 1970s and at the beginning of the new millennium. It was hypothesized that there would be significant differences in morphological and functional characteristics of the Hungarian schoolboy populations, because they were assessed 30 years apart. Means of height, body mass, body mass index (BMI), the sum of five skinfold tests, percentage of body fat, and two running performance times (400 m and 1,200 m) of the boys (N = 3,672) studied in 1975 were compared to those of the boys (N = 3,758) in 2005. Data were analyzed using two-tailed independent samples t tests (p < .05). We observed significant secular changes in body mass and height. In addition, boys in 2005 had significantly more subcutaneous fat compared to 1975. The running times for the two distances were significantly poorer at the time of the second investigation. The remarkable and unfavorable changes in body composition and cardiorespiratory performance were attributed to the continuously decreasing intensity of habitual physical exercise and a lifestyle that had become more sedentary (watching TV playing computer games, etc.). Radical interventions are necessary to reduce these risks associated with the high prevalence of cardiovascular disease in Hungary, and the challenge to resolve the problem requires combined efforts at the educational, societal, corporate, and governmental levels.     

On the foundations of certain theories of turbulence

The author briefly discusses the foundations of modern theories of turbulence based on hydrodynamics equations. He shows that these theories seem to offer only a limited number of possible solutions.     

On the two-dimensional steady flow of a compressible viscous fluid far behind a solid symmetrical body

A number of writers have observed that the particle size distributions obtained from some breakage processes appear to be logarithmico-normal. There have been virtually no attempts to explain this phenomenon. In this paper a statistical model is constructed for a breakage mechanism which will generate size distributions which are asymptotically logarithmico-normal. In this model, F_n(x), the distribution function of the particle sizes, after n steps of the breakage process, is the distribution function of the product of (n + 1) independent random variables and hence, by the central limit theorem, is asymptotically logarithmico-normal.