复杂适应系统理论在管理领域的应用

当前管理模式面临复杂性的挑战,迫切需要实现从简单性向复杂性转变,复杂适应系统(CAS)理论对于解决复杂系统中的各种复杂问题和现象具有重要的指导意义和应用价值。本文简要介绍了CAS理论的基本思想、相关概念和研究问题的方法,就CAS理论在管理领域的应用研究进行了综述,对后续研究中应该注意的问题进行了分析和总结。     

Pore structure of historic and repair Roman cement mortars to establish their compatibility

Mercury porosimetry was applied to the study of pore structure of the historic Roman cement mortars representative of different locations in Europe and time periods as well as different application techniques from architectural castings to in situ formed renders and profiles. Three categories of pores were found to coexist in the mortars. The finest pores, with diameters below 0.1 μm, are present within the hardened aged Roman cement matrix. The larger ‘air’ pores, with diameters between 0.2–2 μm, are due to the evaporation of the excess unbound water and restricted hydration. Pores larger than 2 μm are rare and, in general, can be related to microcracking induced by shrinkage drying and mortar weathering. The mortars have rarely been found to develop a dense fine-porous microstructure characteristic of the ideal conditions of moist-curing; massive architectural castings being the only exception identified. The presence of larger ‘air’ pores was, in turn, almost universally observed. The investigations of the freshly prepared Roman cement mortars have revealed that the restricted hydration could be due to the exposure of the freshly laid surface to dry real-world external environments, a high water-to-cement ratio in the original mortars, or the drawing of water from the stucco mass due to insufficient pre-wetting of the porous masonry. The insufficient reactivity of historic cements, resulting from a high content of over-burned, non-reactive cement components or coarseness of the cement grains, could be another reason for yielding poorly hydrated mortars in the past. In general, Roman cement stuccoes are in an excellent state of preservation in spite of their usual exposure to polluted urban environments for more than a century. Therefore, the coexistence of Roman cement mortars of widely different pore structures has not brought about any problems of incompatibility which field observations could reveal. The Roman cement repair materials have been found to develop pore structures similar to those of historic mortars. Therefore, they are in broad terms compatible with historic masonry or stuccoes. However, the porosity and strength of the repair materials can be controlled by a careful manipulation of the water-to-cement ratio of the mix to adapt them better to the properties of the host material.     

On the role of cultural participation in tourism destination performance: an assessment using robust conditional efficiency approach

The relationship between culture and tourism has been widely investigated from different perspectives. A large strand of literature studies the role of cultural heritage to attract tourists, while a rich bulk of studies on cultural participation investigates the impact of tourism flows on the demand for culture. Another aspect worth investigating relates to the link between cultural participation and the performance of tourism destinations (TDs), as a higher cultural participation in an area could boost the performance in the management of tourism resources. However, so far, this issue has been disregarded in the literature, and this paper aims at filling this gap. Specifically, it studies the effect of cultural participation on TDs’ performance using a conditional efficiency approach that ensures robust inference on the role of environmental factors. We employ data on the Italian regions for the period 2004–2010, and we explore the role of cultural participation for tourism by using several indicators. Our findings offer empirical support to the positive role of cultural participation and, thus, suggest that public cultural policies might also boost the efficiency of the tourism sector.     

Museums,schools and geographies of cultural value

This article explores a paradox and a possibility that have emerged from two pieces of policy-related research concerning educational use of museums within England. The paradox relates to the use of museums which, whilst widely perceived as rather elitist institutions, appear from a postcode analysis of school visits to museums to be visited by large numbers of schools located in areas of social deprivation. The present analysis further explores this paradox, drawing on revised postcode analysis and governmental indices of multiple deprivation and income deprivation affecting children. The analysis supports the contention that museums attracted visits from schools located in areas with some of the highest levels of deprivation, although it suggests that this result needs to be considered in relation to regional differences in areas of social deprivation, the location of museums and the differences between individual and area-based measures of deprivation. Attention is then drawn to the potential of considering museums through a geographical perspective, and specifically through Foucault's notions of primary, secondary and tertiary spatializations. It is argued that primary spatializations encompasses how museums are conceptualized and classified; secondary spatializations concern how various elements of museums are articulated together; and tertiary spatializations relate to the placement of museums in wider societal contexts and processes. It is suggested that the postcode analysis of school visits points both to the significance of considering tertiary spatializations relating to the social circumstances of museum visitors but also raised questions concerning primary spatializations of museums. Attention is drawn to changes in the classification and grouping of museums, and how these often encompass geographically based criteria related to the social reach of museums. The article ends by considering the degree to which museums might seek to further change their primary spatialization to reflect tertiary spatializations relating to cultural value.     

The angiogenetic effect of intramuscular administration of b-FGF and a-FGF on cardiac muscle: the influence of exercise on muscle angiogenesis

Although angiogenetic therapy using recombinant growth factors holds much hope for the treatment of ischaemic diseases, there are still many unanswered questions, including the method of administration, the correct dose of these factors, and the duration of the therapeutic approach. Exercise has also been suggested to induce neovascularizaiton in muscles. We evaluated the angiogenetic effects of the intramuscular administration of basic-fibroblast growth factor (b-FGF) and acidic-fibroblast growth factor (a-FGF) in rat heart, compared with rats who exercised daily. In conclusion, both the intramuscular administration of b-FGF and exercise increased significantly angiogenesis in the heart in contrast to the intramuscular administration of a-FGF, which was ineffective.     

Isokinetic knee extension and vertical jumping: are they related?

The aim of this study was to examine joint power generation during a concentric knee extension isokinetic test and a squat vertical jump. The isokinetic test joint power was calculated using four different methods. Five participants performed concentric knee extensions at 0.52, 1.57, 3.14 and 5.23 rad x s(-1) on a Lido isokinetic dynamometer. The squat vertical jump was performed on a Kistler force plate. Kinematic data from both tests were collected and analysed using an ELITE optoelectronic system. An inverse dynamics model was applied to measure knee joint moment in the vertical jump. Knee angular position data from the kinematic analysis in the isokinetic test were used to derive the actual knee angular velocity and acceleration, which, in turn, was used to correct the dynamometer moment for inertial effects. Power was measured as the product of angular velocity and moment at the knee joint in both tests. Significant differences (P < 0.05) were found between mean (+/- s) peak knee joint power in the two tests (squat vertical jump: 2255 +/- 434 W; isokinetic knee extension: 771 +/- 81 W). Correlation analysis revealed that there is no relationship between the peak knee joint power during the vertical jump and the slow velocity isokinetic tests. Higher isokinetic velocity tests show better relationships with the vertical jump but only if the correct method for joint power calculation is used in the isokinetic test. These findings suggest that there are important differences in muscle activation and knee joint power development that must be taken into consideration when isokinetic tests are used to predict jumping performance.     

Food intake and appetite following school-based high-intensity interval training in 9–11-year-old children

Using a randomised cross-over design, free-living lunch intake and subjective appetite were examined in 10 children (9.8 ± 0.6 years) following high-intensity interval training (HIIT) versus a control sedentary (SED) period, within a school setting. The 22-min HIIT took place during a regular PE lesson and consisted of two rounds of 4 × 30 s sprints. Foods were offered at a regular school lunch immediately following HIIT and SED and were matched between conditions. All food was covertly weighed before and after the meal. Hunger, fullness and prospective consumption were reported immediately before and after HIIT/SED, using visual analogue scales. Heart rate was higher during HIIT than SED (159.3 ± 23.1 vs. 76.9 ± 2.2 bpm, P < 0.05). Lunch energy intake was not different (P = 0.52) following HIIT, compared to SED (2.06 ± 0.35 vs. 2.09 ± 0.29 MJ, respectively). There were no significant differences in macronutrient intake or subjective appetite (P > 0.05). Results suggest that HIIT can be implemented in a PE lesson immediately before lunch, without causing a compensatory increase in food consumption.     

Sophomores speaking: An exploratory study of student research practices

This article describes an exploratory study of the research behaviors of sophomore students at a small liberal arts college. In light of the transitional nature of the sophomore year and the limited data available on the research practices of sophomores, the authors sought to better understand the following: Students’ topic selection, help-seeking behavior, types of sources consulted, source selection criteria, research challenges, and changes in information-seeking behavior from the first year to the sophomore year. This article describes findings from a survey and in-depth interviews, and it offers recommendations for further research.