空间均匀低温氢气燃烧器开发（英文）

目的:设计制造低温的催化氢气燃烧器,并对其进行相关功能性测试。创新点:成功设计并制造出一个集成流量分配器的催化低温氢气燃烧器。方法:1.基于树状分叉方法,设计燃烧器的流量分配器,均匀分配气体到催化表面,并利用熔融沉积成型技术制备原型样机。2.基于测试结果,利用选择性激光熔化技术对燃烧器进行最优化设计。3.对设计的催化燃烧器的相关功能进行验证。结论:1.设计的低温催化燃烧器与传统的非催化燃烧器相比具有很多优势,尤其是实现了无焰均匀低温(约200°C)的产热;这一技术有望运用于化工领域的增材制造。2.本文不但用选择性激光熔融技术制备了最终产品,而且利用了熔融沉积成型技术进行快速的样机制备。3.催化剂多孔载体的调控和催化剂的负载方式研究有望进一步提升燃烧器的综合性能。     

Challenges of talent development in alpine ski racing: a narrative review

Alpine ski racing is one of the most popular sports in many countries; nevertheless, selection disadvantages and severe injuries result in high dropout rates. In this review we summarize existing knowledge about the specific challenges associated with selection bias and injuries, and their effects on talent development in ski racing.

The relative age effect (RAE) appears in all age categories of national Austrian and international alpine ski racing. Relatively younger athletes seem to only have a chance for selection if they are early maturing. Talent selection processes should consider both the biological maturity status as well as the relative age; additionally, a competition system based on a rotating cut-off date might contribute to a reduction of RAE. Youth and adolescent ski racers report lower injury rates compared to World Cup athletes. The knee was the most affected body part in relation to traumatic injuries. The most frequently reported overuse injuries were knee pain (youth) and low back pain (adolescent level). Athlete-related modifiable risk factors were core strength, neuromuscular control, leg extension strength and limb asymmetries. Based on these findings, prevention measures should be expanded to contribute to long-term injury prevention. In future research more multi-disciplinary, longitudinal studies should be performed.     

Mucosal immunity and upper respiratory tract infections during a 24-week competitive season in young ice hockey players

The aim of this study was to examine upper respiratory tract infections (URTI) and their associations with resting saliva and blood immune and endocrine parameters in ice hockey players. Twenty-seven participants (age 16.5 ± 0.5 years) completed the 24-week study period. The counts/concentrations of immune and endocrine markers were compared between healthy-prone athletes (≤2 episodes of URTI during the study period) and illness-prone athletes (≥3 episodes of URTI) and between the URTI state (when athletes had infections) and the healthy state (the time without URTI). There were no differences in concentration/counts of saliva and blood immune and endocrine parameters between the illness-prone and illness-free athletes. Athletes had significantly lower sIgA, sIgA1 and sIgA2 concentrations (sIgA: 119.88 ± 66.88, 144.10 ± 75.0 µg/ml; sIgA1: 90.2 ± 40.64, 108.44 ± 29.8 U; sIgA2: 67.58 ± 30.1, 80.3 ± 25.61 U, respectively) and significantly higher WBC, neutrophil, monocyte and eosinophil count values and IL-1ra concentration at the time when they had symptoms of URTI than in the period without symptoms of infections. There were no differences in salivary cortisol concentration between the period of URTI symptoms and the period without URTI symptoms. In conclusion, we observed lower concentrations of salivary immunoglobulins and higher levels of blood immune parameters during URTI in athletes, which may confirm the suppression of mucosal immunity and initiation responses to pathogenic infections by innate immunity.     

Communications Technology

M.D. Fagan, A History of Engineering and Science in the Bell System: National Service in War and Peace, 1925-1975 (Bell Laboratories, - Whippany Rd., Whippany, N.J. 07981—$15.00).

Daniel M. Costigan Electronic Delivery of Documents and Graphics (New York: Van Nostrand Reinhold, 1978—$21.95)

Konrad K. Kalba, Electronic Message Systems: The Technological, Market and Regulatory Prospects (Cambridge, Mass.: Kalba Bowen Associates, 1978—$30.00, paper),

Starr Roxanne Hiltz and Murray Turoff, The Network Nation: Human Communication via Computer (Reading, Mass.: Addison-Wesley, 1978—$29.50/17.50)

Robert Johansen, Jacques Vallee and Kathleen Spangler, Electronic Meetings: Technical Alternatives and Social Choices (Reading, Mass.: Addison-Wesley, 1979—$15.95)     

Reflections on an Emerging Field: Researching Mathematics Teacher Education

This paper reports a survey of research in mathematics teacher education from 1999 to 2003 done by an international team of five mathematics educators and researchers. The survey included published research in international mathematics education journals, international handbooks of mathematics education and international mathematics education conference proceedings. Some regional sources from various parts of the world were also included. We investigated who was writing, from and in what settings, with what theoretical frameworks, and with what sorts of study designs for what core questions. We also examined the range of findings and conclusions produced in these studies. Our analysis presented here focuses on four themes that stood out from our initial investigation of almost 300 published papers, and systematically elaborated through a focused study of a 160 papers across key journals and conference proceedings in the field. From this vantage point, the paper offers a reflection on the current state of the field of mathematics teacher education research. Our aim is to stimulate discussion that can support the development of the field, not make final pronouncements about its nature. The research presented in this paper was done by five mathematics education researchers, the authors listed above, and presented at ICME10 in Copenhagen in July 2004. This Survey Team (Survey Team 3) was nominated by the International Program Committee for the Congress and asked to survey “Professional Development of Mathematics Teachers” and present this in a plenary at the Congress. A copy of the presentation can be viewed at: http://www.wits.ac.za/jadler/presentations.html. An earlier version of this paper will also appear in the ICME10 proceedings.     

Development of a spatially uniform low-temperature hydrogen combustor

Examples of the use of additive manufacturing and rapid prototyping in a range of applications are of great interest in order to emphasize their role in development and production technology. In this study, a catalytic low temperature burner for H₂ on a lab scale with an integrated flow distributor was designed, manufactured, and tested for functionality. Based on a theoretical approach, a flow distributor for the burner was designed and a prototype was built using fused deposition modeling (FDM). Based on test results, an optimized version of the burner was then designed and manufactured using selective laser melting (SLM). The functionality of the designed catalytic burner was proven. Several advantages were found in comparison to conventional non-catalytic burners. In particular, flameless uniform low temperature heat generation with temperatures of about 200 °C could be realized. This contribution highlights the potential of additive manufacturing in chemical engineering. Not only was the final product built using SLM, but also during the development process, FDM was used for rapid prototyping.     

State-Dependent Memory in Infants

Why do infants remember some things and not others? Human infants frequently cycle through different states such as calm attentiveness, wakeful activity, and crying. Given that cognitive processes do not occur in isolation, such fluctuations in internal state might influence memory processing. In the present experiment, declarative memory in 9-month-old infants (N = 96) was heavily state dependent. Infants exhibited excellent retention of a deferred imitation task after a 15-min delay if their state at encoding was identical to their state at retrieval (e.g., calm). Infants failed to exhibit retention if their state at encoding was different from their state at retrieval (e.g., calm vs. animated). Infant memory processing depends on internal cues.     

The ‘Civic-minded’ Professional? An exploration through Hannah Arendt’s ‘vita activa’

Recent reform initiatives calling for ‘civic’ (‘public-good’ or ‘democratic’) professionalism can be seen as a response to the widely reported decline in public trust in the professions and an attempt to partially remedy this problem through a more publically engaged professionalism. The author draws on the political philosophy of Hannah Arendt, identifying the strong, albeit in the professionalism literature rarely acknowledged, affinities between civic professionalism and her concept of action as (collective) freedom through public deliberation. Using the three modalities of the active life that Arendt discusses in The Human Condition (labour, work and action) as analytical tools, the author suggests that changing conditions in the public sector have led to professional life increasingly taking on the forms of labour and work, at the expense of action. The implications of these developments are highlighted before the author proceeds to show that a professional life oriented strongly towards action is consistent with ‘civic’ professionalism based on community engagement. Some of the main approaches traditionally taken to promote a civic orientation among university students are noted; the article concludes with a discussion of how the specific concepts underlying Arendtian action can be put to work in university pedagogies to intentionally promote the public ‘civic-minded professional’.