663 research outputs found
Market power and the need for regulation in the German airport market
With the increasing profit orientation of German airport operators the question as to weather they possess market power is gaining more importance. Whereas there have been some studies about the degree of market power of individual airports in countries as Australia and Great Britain, the German airport market has not yet been studied in detail. This paper is a part of a research project that tries to assess market power in this market. It indicates which of the 35 examined German airports possess market power and therefore need special regulatory attendence. We calculate a substitution coefficient for inter-airport competition that quantifies the quality of the best substitute for a certain airport. It is defined as the proportion of inhabitants within the relevant regional market of an airport that consider another airport, which has been identified as meeting the demands of the airlines, to be a good substitute from their perspective as well. The analysis is complemented by an assessment of intermodal substitution and countervailing power of airlines. The study gives strong indication that 23 out of the 35 German airports do not possess relevant market power. In contrast to this, four airports (HAM, FRA, MUC, STR) and Berlin Airport System (THF, TXL, SXF) have strong, five (BRE, DRS, LEJ, NUE, HAJ) have modest market power. The results provide a basis for the construction of an efficient regulatory framework for the German airport market.airport competition, counterveiling power, market power, substitution
Measuring Efficiency of German Bus Public Transport
This paper quantifies the technical efficiency of German bus companies and elaborates on the main factors influencing their performance. Efficiency is measured with a stochastic production frontier. We test for the impact on efficiency of ownership structure and participation at tendering. Furthermore, we investigate the influence on efficiency when a bus company is a part of a multi-product enterprise. The results yield insights how public bus companies might improve their performance in order to cope with the changing market environment. The mean technical efficiency of the investigated bus companies is around 87 percent. Bus companies with participation at tendering show a significantly higher mean efficiency than other companies. The ownership structure has no influence on technical efficiency.Stochastic Frontier Analysis, Production Function, Public Transport, Efficiency Analysis,
Durchsetzung von Partialinteressen in politischen MĂ€rkten am Beispiel Metrorapid
Vieles spricht gegenwĂ€rtig dafĂŒr, dass der Transrapid in Deutschland auf Kurzstrecken gebaut werden dĂŒrfte, obwohl konkurrierende Verkehrsinfrastrukturprojekte einen sehr viel höheren volkswirtschaftlichen Nutzen aufweisen. Warum hat der Metrorapid gute Realisierungschancen? Wie kommt es, dass sich auf politischen MĂ€rkten Partialinteressen gegen die Interessen der Allgemeinheit durchsetzen können? --
Variation in sport participation, fitness and motor coordination with socioeconomic status among Flemish children
Socioeconomic status (SES) is often indicated as a factor that influences physical activity and associated health outcomes. This study examined the relationship between SES and sport participation, morphology, fitness and motor coordination in a sample of 1955 Flemish children 6-11 years of age. Gender, age and SES-specific values for morphologic dimensions, amount and type of sport participation and fitness and motor coordination tests were compared. SES was positively and significantly associated with sport participation and sports club membership in both sexes. Although differences were not consistently significant, morphologic dimensions and tests of fitness and motor coordination showed a trend in favor of children from higher SES. The results suggest that public and local authorities should consider providing equal opportunities for children in all social strata and especially those in the lower SES to experience the beneficial effects of sport participation through which they can enhance levels of physical fitness and motor coordination
Assessment of reliability in isokinetic testing among adolescent basketball players
Background. The reproducibility of day-to-day testing of isokinetic concentric and eccentric muscular actions among adolescent basketball players aged 14 to 16 years and relationships of mean within-subject variation in two isokinetic testing sessions with chronological age, biological maturation (estimated age at peak height velocity), training experience, body size, lower-body morphology, and initial strength performance were evaluated.
Material and Methods. The sample included 27 basketball players who completed replicate test sessions of 5 repetitions of reciprocal concentric and eccentric knee extensions and flexions at 60 degrees s(-1). A randomly selected subsample of 8 players completed a third testing session to confirm reliability estimates.
Results. Coefficients of variation (CV) between sessions 1 and 2 ranged from 8.1% to 17.4%, and intraclass coefficients (ICCs) ranged from 0.72 to 0.89. For sessions 1 and 3, CVs ranged from 3.9% to 6.0%, and ICCs ranged from 0.95 to 0.99. The initial level of strength of eccentric knee flexion (r=-0.43) and eccentric knee extension (r=-0.42) were correlated (P<0.05) with eccentric knee extension within-variation between two sessions. Training experience (r=-0.37, P<0.05) and initial values of concentric knee flexion (r=-0.62, P<0.01) were correlated with concentric knee flexion within-subject differences. Within-subject variation of eccentric knee extension was correlated (P<0.05) with chronologic age (r=0.41), estimated age at peak height velocity (r=-0.38), body size (r=0.41 to 0.47), and leg volume (r=0.39).
Conclusions. Familiarization sessions may improve the reliability of concentric and eccentric knee isokinetic strength testing at 60 s(-1) in adolescent basketball players. Age, maturity status, and training experience of young athletes should be considered when testing knee isokinetic strength at 60 degrees s(-1)
Relative Age and Maturation Selection Biases in Academy Football
This study examined the simultaneous effects of relative age and biological maturity status upon player selection in an English professional soccer academy. A total of 202 players from the U9 to U16 age groups, over an eight-year period (total of 566 observations), had their relative age (birth quarter) and biological maturity (categorised as late, on-time or early maturing based upon the Khamis-Roche method of percentage of predicted adult height at time of observation) recorded. Players born in the first birth quarter of the year (54.8%) were over-represented across all age groups. A selection bias towards players advanced in maturity status for chronological age emerged in U12 players and increased with age; 0% of players in the U15 and U16 age group were categorised as late maturing. A clear maturity selection bias for early maturing players was, however, only apparent when the least conservative criterion for estimating maturity status was applied (53.8% early and 1.9% late maturing in the U16 age group). Professional football academies need to recognise relative age and maturation as independent constructs that exist and operate independently. Thus, separate strategies should perhaps be designed to address the respective selection biases, to better identify, retain and develop players
Developmental fitness curves: Assessing sprint acceleration relative to age and maturity status in elite junior tennis players
Background The influence of maturity-status on athletic performance is reasonably well-documented. Methodological and practical issues of assessment and lack of longitudinal data have impacted the success of various models. Aim To develop age- and sex-specific developmental curves for sprint acceleration in elite youth tennis players and to address variation in performance relative to chronological and biological age. Subjects and methods Measures of acceleration were available for 3120 elite youth tennis players aged 8â15âyears attending National and Regional Talent Identification days. Variation in acceleration by chronological and estimated biological ages was evaluated in corresponding data for an independent sample of elite youth players 8.9 to 15.1âyears of age. Results Acceleration varied as a function of chronological and biological age relative to developmental curves. Early maturing males and females had significantly poorer performances when acceleration was considered relative to biological age. Significant discrepancy in percentiles relative to biological versus chronological ages was also evident between early and late maturing players of each sex. Conclusion Evaluating performance relative to developmental curves and maturity status may be a practical means of monitoring long-term athlete development in tennis
Motor coordination, physical activity and fitness as predictors of longitudinal change in adiposity during childhood
The purpose of this study was to examine the influence of motor coordination (MC), physical fitness (PF) and physical activity (PA) on the development of subcutaneous adiposity in a sample of children followed longitudinally from 6 to 10 years of age. Participants were 142 girls and 143 boys. Height, weight, and the triceps and subscapular skinfolds were measured annually between the ages of 6 and 10 years. PA was estimated with the GodinâShephard questionnaire. MC was evaluated with the Körperkoordination Test fĂŒr Kinder (KTK) test battery, and PF was assessed with four Fitnessgram tests: curl-ups (CU), push-ups (PU), trunk-lifts (TL) and one mile run/walk (MRW). Hierarchical linear modelling with MC, PF items and PA as predictors of the sum of two skinfolds (SKF) was used. The results showed that boys and girls differed significantly in SKF at baseline (girls: 19.7 mm; boys: 16.6 mm). Three PF items (CU, PU and MRW) and MC had a positive influence on SKF. For each unit improvement in CU, PU, MRW and MC, SKF was reduced by 0.06, 0.04, 0.06 and 0.12 mm, respectively. In conclusion, motor coordination, muscular strength and endurance, and aerobic endurance attenuated the accumulation of subcutaneous adipose tissue during childhood
Physical activity patterns during school recess : a study in children 6 to 10 years old
The aims of this study were to characterize the spontaneous physical activity of children during school recess, and to estimate variation in physical activity associated with gender and age. A MTI actigraph (Model 7164) was used with a sample of 140 boys and 131 girls, 6 to 10 years of age. MTI counts were converted to METs using a regression equation developed for children. The number and average duration of periods of activity by intensity were calculated for each child during a 30 minute recess: rest or mild physical activity (†2.9 METs), moderate physical activity (3.0-5.9 METs,), vigorous physical activity (6.0-8.9 METs) and very vigorous physical activity (℠9.0 METs). Boys and girls spent about 50% of the recess in physical activity. Physical activity was characteristically done in very short bursts with intervals of rest or mild physical activity. The number of episodes of physical activity of all intensity levels was lower in older children while the inverse occurred at rest or mild physical activity. Boys engaged in higher intensity activity than girls and in general spent more recess time in physical activity
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