Mixed ℓ2 and ℓ1-norm regularization for adaptive detrending with ARMA modeling

In this paper, the problem of detrending a time series and/or estimating a wandering baseline is addressed. We propose a new methodology that adaptively minimizes different regularized cost functions by introducing an ARMA model of the underlying trend. Mixed ?₁/?₂-norm penalty functions are taken into consideration and novel RLS and LMS solutions are derived for the model parameters estimation. The proposed methods are applied to typical trend estimation/removal problems that can be found in the analysis of economic time series or biomedical signal acquisition. Comparisons with standard noncausal filtering techniques are also presented.     

Contractual governance and the choice of dispute-resolution mechanisms: Evidence on technology licensing

In fast-paced and knowledge-intensive environments, licensing partnerships can be powerful levers for market expansion. Research on the management of technology-oriented licenses has nonetheless pointed out the risks of corrosive disputes caused by conflicting interests or misunderstandings among licensing partners. The choice made ex ante on mechanisms for resolving potential disputes is of prime importance in the execution of licensing exchanges. Although the legal literature has widely emphasized the advantages of arbitration towards litigation, public ordering remains the “default” option in managers’ eyes. By adopting a transaction cost economics logic, our study explores the conditions under which licensing partners may prefer arbitration over public ordering during the contractual-design phase. In accordance with our theoretical arguments, findings show that the occurrence of arbitration provisions increases when the coordination orientation adopted by licensing partners is extensive. In situations where both monitoring and coordination orientations are simultaneously extensive, results reveal a greater propensity to prefer arbitration over public ordering. Our research therefore supports the view that corporate decision-makers tend to favor the conciliatory stance and compromising awards typically associated with arbitration, only when exchanges are expected to be highly coordinative. Their preference for arbitration over litigation is magnified when the coordination orientation develops alongside the monitoring orientation.     

Technology and employment: Mass unemployment or job creation? Empirical evidence from European patenting firms

This paper explores the possible job creation effect of innovation activity. We analyze a unique panel dataset covering almost 20,000 patenting firms from Europe over the period 2003–2012. The main outcome from the proposed GMM-SYS estimations is the labor-friendly nature of innovation, which we measure in terms of forward-citation weighted patents. However, this positive impact of innovation is statistically significant only for firms in the high-tech manufacturing sectors, while not significant in low-tech manufacturing and services.     

Effect of 6-weeks WBVT on the behaviour of the lower limb muscle fibres during vertical jumping

The purpose of the current study was to examine the effect of 6 weeks of whole body vibration training (WBVT) on body composition, muscle activity of the gastrocnemius and vastus lateralis, gastrocnemius muscle architecture (static and dynamic) and ground reaction forces (performance jump) during the take-off phase of a countermovement jump in young healthy adult males. A total of 33 men (23.31 ± 5.62 years) were randomly assigned to a whole body vibration group (experimental group, EG_WBVT: n = 17; 22.11 ± 4.97 years) or a control group (CG: n = 16; 24.5 ± 6.27 years). The total duration of the intervention phase (WBVT) was 6 weeks with a frequency of 3 sessions per week. Statistically significant differences were observed (P ≤ 0.05) between pre- and post-test in the power peak (Δ 1.91 W · kg^?1; P = 0.001), take-off velocity (0.1 cm · s^?1; P = 0.002) and jump height (Δ 0.4 cm; P = 0.002) for EG_WBVT. There were no statistically significant differences in any of the body composition and muscle architecture variables. Moreover, no significant differences were found between EG_WBVT and CG nor changes in muscle activity during take-off phase of the gastrocnemius and vastus lateralis pre- versus post-training. This study suggests that a 6-week WBVT programme with increasing intensity improves jump performance but does not alter muscle activity nor muscle architecture in healthy young men.     

The effects of service convenience and perceived quality on perceived value,satisfaction and loyalty in low-cost fitness centers

Due to its importance in fitness centers, a number of authors have explored and analyzed loyalty. However, two characteristics not yet examined are service convenience in fitness center chains and low-cost fitness centers (an emerging business model). In the present study, the authors sought to understand the relationship among perceived quality and service convenience on perceived value, satisfaction, and client loyalty in low-cost fitness centers. Clients (N = 763; 381 women and 382 men) from three low-cost Spanish fitness centers were surveyed, revealing a positive relationship among the variables studied. Findings demonstrate the importance of proper management of non-monetary sacrifices and perceived quality by the managers of these sport organizations, since client loyalty could depend on factors of these emerging sport models.     

The role of the referee in physical education lessons: student experience and motivation

Introduction: Social roles in physical education (PE) classes have been much studied, especially mentoring and coaching roles. The studies have shown that mentoring and coaching are beneficial not only for motor learning, but also for methodological and social learning. To our knowledge, the role of the student referee in PE lessons has never been specifically studied. Yet refereeing is essential in many sports, including team sports, and provides an experience of responsibility that many teachers want to offer their students. Encouraging students to take on this role can nevertheless be difficult.

Objective: The objective of the present study was to gain access to students’ lived experiences as referees in order to determine their strategies for being effective. We particularly wanted to determine which concerns organized their activity so that we could identify a refereeing typology that would be useful for PE teaching. Our study is original in that we did not rely exclusively on experiential data to understand student refereeing activity. We also collected data on the students’ motivation in order to better understand their experiences. For this purpose, the study was conducted within the methodological framework of course-of-action theory and self-determination theory.

Method: Seventy-four students from three classes in the third year of middle school (about 13 years old) participated in the study. Among them, four (two girls and two boys and not experts in the sports in which they were going to referee) had volunteered to be filmed and to participate in self-confrontation interviews. The other students completed two questionnaires to provide information on their motivation for refereeing. The situations studied were basketball and handball matches held at the end of the lessons.

Two categories of data were collected: qualitative and quantitative. The qualitative data were based on audiovisual recordings of the students as they refereed matches and verbalization data from self-confrontation interviews; these data were used to document the students’ courses of experience during the activity period under study. The quantitative data were collected using two questionnaires, one to assess the determinants of motivation and the other to assess self-determined motivation.

Results and discussion: The qualitative analysis highlighted three typical student involvements: fulfilling the role of referee, getting help, and occasionally dropping out of the role. The quantitative analysis revealed that the students in the social role of referee mainly expressed amotivation, external regulation, and intrinsic motivation toward knowledge and accomplishment.

The results are discussed around two major points: (1) the students’ strategies of alternation from which their refereeing activity emerged and (2) proposals for PE teacher interventions.     

Dynamics of student interactions: an empirical study of orienteering lessons in physical education

Introduction: Many studies in physical education (PE) have sought to identify and categorize the modes of student interaction in order to gain greater insight into the nature of cooperative activity. More others recent studies have examined how modes of interaction evolve on the basis of the modes of collective activity that they generate. These studies have shown to describe and explain the interactions among individuals and the processes they generate, which then lead to the construction, deconstruction or reconstruction of different interaction modes. Although some studies have sought to describe the dynamics of student interactions, very few have quantified these dynamics. By doing so, however, researchers might gain a new perspective on student interaction modes that inspires new designs for teaching in PE, thereby having professional impact. The present study extends this research by investigating the dynamics of student interaction, with a focus on the emergence of interaction modes during orienteering lessons. For this purpose, the study was conducted within the methodological framework of course of action theory, which is an effective approach for examining activity in natural situations to provide insight into the experience of activity from the actors perspective.

Method: The study was conducted in two classes of seventh-grade students (about 12 years old) in which 16 students volunteered and were available for post-action interviews immediately after the lessons under study. These volunteers were placed in eight affinity-based dyads. The teachers planned orienteering lessons at similar levels of difficulty and duration but modified the lessons across a range of contextual features. Two categories of data were collected: (1) data from audiovisual recordings as the students searched for the checkpoints and (2) verbalization data during the post-action interviews with the students. The data were processed in two steps: one qualitative, the other quantitative. The qualitative step consisted of processing the data of the student experiences to characterize their interactions in the three different contexts. In the quantitative step, the data from the first step were graphically represented to depict the interaction dynamics within the student dyads.

Results and discussion: The qualitative analysis showed the emergence of three modes of student interaction shared across each learning context: co-construction, confrontation and delegation. The quantitative analysis revealed the percentages of the different modes of interaction and therefore characterized the interaction dynamics. Our results showed that the interaction dynamics within the dyads were both unique and similar in the task contexts in terms of both ratios of change and distribution. Results are discussed across two major points of interest: (1) the observation of the same interaction modes whatever the context yet with quite different dynamics and (2) proposals for PE teacher interventions.     

Engines at top speed! Using the adventures of a comic book motorsports hero as an approach to understanding recent French history

Jean Graton created a series of comic books called Michel Vaillant, and its motorsports hero bore the same name. Michel Vaillant made his first appearance in 1957 in the weekly Tintin. Young French boys who loved adventure, sports and car racing greeted this publication with great enthusiasm. We studied the first series of Michel Vaillant, composed of 16 comic books produced in the 1960s. We have departed from traditional approaches and have based our method on the analysis of the sources of Graton’s inspiration. We link these sources to the comics’ text bubbles, visual signs and iconic meanings of the drawings. Our analysis of the comics’ iconography based on the establishment of a mass culture dedicated to the automobile brings to light the existence of an urge to go beyond the limits of tradition. Our research highlights that the success of Michel Vaillant is due, in the main, to the series’ detailed knowledge of the automobile sports industry, and to the myths of speed, youth and progress that it promulgates – myths in which its young male readers could see themselves reflected and which would also prepare them for the future.     

Contribution of uncertainty in estimation of active drag using assisted towing method in front crawl swimming

Active drag force in swimming can be calculated from a function of five different variables: swim velocity, tow velocity, belt force, power output and exponent of velocity. The accuracy of the drag force value is dependent on the accuracy of each variable, and on the contribution of each variable to drag estimation. To calculate uncertainty in drag value, first the derivatives of the active drag equation with respect to each variable were obtained. Second, these were multiplied by the uncertainty of that variable. Twelve national age and open level swimmers were recruited to complete four free swimming and five active drag trials. The uncertainties for the free and the tow swim velocities, and for the belt force, contributed approximately 5–6% and 2–3% error, respectively, in calculation of drag. The result of the uncertainty of the velocity exponent (1.8–2.6) indicated a contribution of about 6% error in active drag. The contribution of unequal power output showed that if a power changed 7.5% between conditions, it would lead to about 30% error in calculated drag. Consequently, if a swimmer did not maintain constant power output between conditions, there would be substantial errors in the calculation of active drag.     

Effects of inspiratory muscle training in professional women football players: a randomized sham-controlled trial

This study was conducted to determine the effects of inspiratory muscle training (IMT) on respiratory and peripheral muscles oxygenation during a maximal exercise tolerance test and on repeated-sprint ability (RSA) performance in professional women football players. Eighteen athletes were randomly assigned to one of the following groups: SHAM (n = 8) or IMT (n = 10). After a maximal incremental exercise test, all participants performed (on a different day) a time-to-exhaustion (Tlim) test. Peripheral and respiratory muscles oxygenation by near-infrared spectroscopy, breath-by-breath ventilatory and metabolic variables, and blood lactate concentration were measured. The RSA test was performed on a grass field. After a 6 week intervention, all athletes were reevaluated. Both groups showed increases in inspiratory muscles strength, exercise tolerance and RSA performance, however only the IMT group presented lower deoxyhemoglobin and total hemoglobin blood concentrations on intercostal muscles concomitantly to an increased oxyhemoglobin and total hemoglobin blood concentrations on vastus lateralis muscle during Tlim. In conclusion, these results may indicate the potential role of IMT to attenuate inspiratory muscles metaboreflex and consequently improve oxygen and blood supply to limb muscles during high-intensity exercise, with a potential impact on inspiratory muscle strength, exercise tolerance and sprints performance in professional women football players.