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1.
Sustainable technologies challenge prevailing business practices, especially in industries that depend heavily on the use of fossil fuels. Firms are therefore in need of business models that transform the specific characteristics of sustainable technologies into new ways to create economic value and overcome the barriers that stand in the way of their market penetration. A key issue is the respective impact of incumbent and entrepreneurial firms’ path-dependent behaviour on the development of such new business models. Embedded in the literature on business models, this paper explores how incumbent and entrepreneurial firms’ path dependencies have affected the evolution of business models for electric vehicles. Based on a qualitative analysis of electric vehicle projects of key industry players over a five-year period (2006–2010), the paper identifies four business model archetypes and traces their evolution over time. Findings suggest that incumbent and entrepreneurial firms approach business model innovation in distinctive ways. Business model evolution shows a series of incremental changes that introduce service-based components, which were initially developed by entrepreneurial firms, to the product. Over time there seems to be some convergence in the business models of incumbents and entrepreneurs in the direction of delivering economy multi-purpose vehicles.  相似文献   
2.
Abstract High physical fitness in childhood and adolescence is positively associated with favourable health-related outcomes. Our aim was to examine the relationship between relatives' (father, mother, brother, sister, and best friend) physical activity engagement and encouragement on adolescents' physical fitness. Adolescents were part of the HELENA study, a multi-centre study conducted in 10 cities from nine European countries in 2006-2008. Participants were 3288 adolescents (48% boys, 52% girls) aged 12.5-17.5 years with valid data on at least one of the three fitness variables studied: muscular strength (standing long jump), speed/agility (4×10 m shuttle run), and cardiorespiratory fitness (20 m shuttle run). The adolescents reported their relatives' physical activity engagement and encouragement. Analysis of covariance showed that relatives' physical activity engagement (father, mother, brother, and best friend) was positively related to cardiorespiratory fitness (P?相似文献   
3.
Abstract

This report aims (1) to examine the association between seasonality and physical activity (PA) and sedentary time in European adolescents and (2) to investigate whether this association was influenced by geographical location (Central-North versus South of Europe), which implies more or less extreme weather and daylight hours. Valid data on PA, sedentary time and seasonality were obtained in 2173 adolescents (1175 females; 12.5–17.5 years) included in this study. Physical activity and sedentary time were measured by accelerometers. ANCOVA was conducted to analyse the differences in PA and sedentary time across seasons. Results showed that girls had lower levels of moderate to vigorous PA (MVPA) and average PA, and spent more time in sedentary activities in winter compared with spring (all P < 0.05). Stratified analyses showed differences in PA and sedentary time between winter and spring in European girls from Central-North of Europe (P < 0.05 for sedentary time). There were no differences between PA and sedentary time across seasonality in boys. In conclusion, winter is related with less time spent in MVPA, lower average PA and higher time spent in sedentary activities in European adolescent girls, compared with spring. These differences seem to mainly occur in Central-North Europe.  相似文献   
4.
Abstract

The aim of this study was to compare equations for estimating percentage body fat from skinfold thickness in elite sport climbers by assessing their agreement with percentage body fat measured using dual-energy X-ray absorptiometry (DXA). Skinfold thickness was measured in a convenience sample of 19 elite sport climbers [9 women and 10 men; mean age 31.2 years (s = 5.0) and 28.6 years (s = 3.6), respectively]. Percentage body fat was estimated using 17 different equations, and it was also measured by DXA. A significant inter-methods difference was observed for all equations, except for Durnin's equation in men (inter-methods difference: ?0.57% and ?0.29%; 1.96 s: 5.56 and 5.23 for Siri's and Brozek's equation, respectively) and women (inter-methods difference: ?0.67% and ?1.29% for Siri's and Brozek's equation, respectively), and for Wilmore's equation using Siri's body fat equation in women (inter-methods difference: ?1.86%). In women, the limits of agreement were lower when using Durnin's equation compared with Wilmore's equation (1.96 s: 3.86% and 5.13%, respectively). In conclusion, of the 17 studied equations, Durnin's equation was the most accurate in estimating percentage body fat in both male and female elite climbers. Therefore, Durnin's equation could be used to assess percentage body fat in elite sport climbers if more accurate methods are not available. The generalizability of the results is limited by the fact that the sample was not selected at random.  相似文献   
5.
A highly touted feature of the so-called global “revolution” in higher education is the trend to use information technology to reach a broader clientele. Although there is evidence that students may be learning the material in on-line courses as well as in traditional face-to-face universities, how well students learn content is not the only reason they persist to a degree, and student persistence is an important goal of higher education institutions. In this paper, we make the case that the life conditions for students attending virtual universities are different from those of “traditional” students in face-to-face universities, and that this difference puts a particular (largely non-pecuniary) premium on time to degree. With our data from a Catalan virtual university, the Open University of Catalonia (UOC), we are able to test this hypothesis directly by using the heterogeneous degree structure of the Catalonian/Spanish higher education system to estimate whether the number of courses required to get various degrees (the length of the degree program) is significantly related to student persistence. The study analyzes several cohorts of students (those who entered in 2000–2003) studying in the UOC and estimates the factors that influence their degree completion. We find that the completion rate is generally low, but that students taking shorter degree courses at the UOC are much more likely to complete their degrees. This suggests that, given their clientele, on-line universities operate under very different constraints from their face-to-face counterparts. Our results are important for higher educational researchers, who have mainly focused on younger populations attending face-face universities. They also can serve university administrators who launch distance education degree programs and make high stakes decisions about them with little of no information on the likely behavior of their older students, and can serve employers who are deciding whether to subsidize their employees to take advanced degrees through on-line programs of study.  相似文献   
6.
Nästesjö  Jonatan 《Minerva》2021,59(2):237-259
Minerva - There is a lack of objective evaluative standards for academic work. While this has been recognized in studies of how gatekeepers pass judgment on the works of others, little is known...  相似文献   
7.
The increasing opportunities created for adults by on‐line distance universities raise important issues about the payoff to such education. This study uses a unique set of survey data gathered by the Open University of Catalonia (UOC) in 2009 to estimate the earnings gains of the 2000–2003 cohorts of UOC students in six programmes of study over an average six‐year time frame between entering and one year after leaving their studies. It compares their gains with the earnings gains of comparable full‐time workers in the Spanish labour force by age, education level, and gender. The results show that those who studied in UOC's two‐year second‐cycle degree programmes had positive relative earnings gains but those in three‐year first‐cycle degree programmes did not. The study further discusses why adult learners might nevertheless study toward degrees for which payoffs appear low.  相似文献   
8.
ABSTRACT

Research on the use of Massive Open Online Courses (MOOCs) for teacher professional development (TPD) and the characteristics of their participants is scarce. This article presents a case of a MOOC initiative supported by the Spanish Ministry of Education aiming at teachers’ professional development on the use of ICT for teaching and learning. The analysis is focused on (a) the sociodemographic and school characteristics of the teachers participating in MOOCs; (b) their experience and beliefs about lifelong learning; and (c) the relevance of MOOCs for their work. By contrasting the characteristics of the participants in this initiative with the characteristics of the whole population of teachers in Spain, and a sample of Spanish participants in MOOCs not aimed at TPD, the article sheds light on the specificities of the teachers who use this way of TPD. The results have implications for the design of programmes aimed to develop MOOCs for TPD.  相似文献   
9.
PurposeThis study was aimed to analyze the mediation role of cardiorespiratory fitness (CRF) on the association between fatness and cardiometabolic risk scores (CMRs) in European adolescents.MethodsA cross-sectional study was conducted in adolescents (n = 525; 46% boys; 14.1 ± 1.1 years old, mean ± SD) from 10 European cities involved in the Healthy Lifestyle in Europe by Nutrition in Adolescence study. CRF was measured by means of the shuttle run test, while fatness measures included body mass index (BMI), waist to height ratio, and fat mass index estimated from skinfold thicknesses. A clustered CMRs was computed by summing the standardized values of homeostasis model assessment, systolic blood pressure, triglycerides, total cholesterol/high-density lipoprotein cholesterol ratio, and leptin.ResultsLinear regression models indicated that CRF acted as an important and partial mediator in the association between fatness and CMRs in 12–17-year-old adolescents (for BMI: coefficients of the indirect role β = 0.058 (95% confidence interval (95%CI): 0.023–0.101), Sobel test z = 3.11 (10.0% mediation); for waist to height ratio: β = 4.279 (95%CI: 2.242–7.059), z =3.86 (11.5% mediation); and for fat mass index: β = 0.060 (95%CI: 0.020–0.106), z = 2.85 (9.4% mediation); all p < 0.01).ConclusionIn adolescents, the association between fatness and CMRs could be partially decreased with improvements to fitness levels; therefore, CRF contribution both in the clinical field and public health could be important to consider and promote in adolescents independently of their fatness levels.  相似文献   
10.
Identifying factors related to physical activity levels in young people is important for a more efficient health promotion. The aims of this study were to assess physical activity levels in a national sample of urban Spanish adolescents, and to examine the association between significant others' physical activity (father, mother, brother, sister, and close friends) and that of the adolescents. The present study comprised 2260 adolescents (1157 boys, 1103 girls) aged 13.0-18.5 years participating in the AVENA Study. Both the adolescents' physical activity and that of their relatives and close friends was assessed by questionnaire. The odds of being active were higher in boys than girls (odds ratio?=?2.79, 95% confidence interval?=?2.34-3.33) and tended to decrease across age groups in both boys and girls. Father's and older brother's physical activity was associated with boys' physical activity, while that of any significant other was associated with girls' physical activity. When both parents reported being active, boys had nearly two times higher odds of being active and girls had nearly three times higher odds of being active. The physical activity levels of Spanish adolescents are in line with those previously reported. Physical activity levels in girls are strongly related to the physical activity of any significant other, whereas physical activity levels in boys are only related to their male relatives' physical activity.  相似文献   
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