Multi-segmental movements as a function of experience in karate

Karate is a martial art that partly depends on subjective scoring of complex movements. Principal component analysis (PCA)-based methods can identify the fundamental synergies (principal movements) of motor system, providing a quantitative global analysis of technique. In this study, we aimed at describing the fundamental multi-joint synergies of a karate performance, under the hypothesis that the latter are skilldependent; estimate karateka’s experience level, expressed as years of practice. A motion capture system recorded traditional karate techniques of 10 professional and amateur karateka. At any time point, the 3D-coordinates of body markers produced posture vectors that were normalised, concatenated from all karateka and submitted to a first PCA. Five principal movements described both gross movement synergies and individual differences. A second PCA followed by linear regression estimated the years of practice using principal movements (eigenpostures and weighting curves) and centre of mass kinematics (error: 3.71 years; R2 = 0.91, P ? 0.001). Principal movements and eigenpostures varied among different karateka and as functions of experience. This approach provides a framework to develop visual tools for the analysis of motor synergies in karate, allowing to detect the multi-joint motor patterns that should be restored after an injury, or to be specifically trained to increase performance.     

Verification of the stomatal conductance of Nebbiolo grapevine

Wine is one of the most important Italian export products, and Nebbiolo is one of the most respected Italian grapes. In the summer of 2007, a measurement campaign was carried out in a Nebbiolo vineyard located in Vezza d＇Alba, near Cuneo, Italy. Using a gauge of trade gases and some other instruments, we recorded the stomatal conductance and also some physiological parameters useful for estimating the dependence of stomatal conductance on environmental variables. The goal of this experiment was improving the parameterization of grapevine evapotranspiration through the assessment of the stomatal conductance and, in particular, of the functional dependence of the stomatal conductance on the following variables： the photosynthetically active radiation, the atmospheric temperature, the atmospheric moisture deficit, and the carbon dioxide concentration. The observations allowed us to check and, in some cases, to adapt the existing general parameterizations found in literature. The results showed some significant differences with the existing parameterizations concerning the atmospheric temperature, the atmospheric moisture deficit, and the carbon dioxide concentration. The parameterizations obtained in this experiment, although referring to a specific plant and site （namely the Nebbiolo at Vezza d＇Alba）, could allow assessment of the best environmental conditions under which the Nebbiolo grapevine production is the best, and in future could be tested for other grapevines or climates.     

Trans-illumination and trans-irradiation with digital cameras: Potentials and limits of two imaging techniques used for the diagnostic investigation of paintings

During the past two decades, thanks to the rapid development of solid-state-based sensor technology, digital imaging emerged as one of the most attractive research areas for the noninvasive investigation of paintings and flat artworks. In particular, the commercial availability of high-performance digital cameras opened up new perspectives to transmitted imaging techniques, such as trans-illumination and trans-irradiation, which are based on the acquisition of the visible (Vis) and near infrared (NIR) radiation, respectively, transmitted through the object. Until recently, these techniques were indeed considered to be unsuitable for applications on artefacts, because of the risks of overheating and overexposure to the light of the object under analysis. Nowadays, with the new-generation digital cameras, transmitted imaging can be reconsidered as a possible tool for noninvasive diagnostics on paintings on canvas. These techniques have been proven to be effective for the examination of hidden details, such as underlying drawing, for a study of the pictorial style or the executive techniques, as well as for assessing the state of conservation of the supports. Both trans-illumination and trans-irradiation can be easily implemented by means of professional photographic digital cameras, and therefore offer a valuable alternative to the more expensive well-established methodologies, such as X-ray radiography. In some cases, they are found to be complementary to the conventional techniques in revealing details of the underlying paint layers. Potentials and limits of transmitted imaging techniques are discussed in this paper, starting from three case studies of oil-paintings on canvas that belong to the permanent collection of the Gallery of modern art at the Pitti Palace in Florence.     

Classification and Subject Indexing Issues at a Mexican Library Specializing in Law Research

Abstract

Subject indexing and classification of law resources is a complex issue due to several factors: specialized meanings of legal terms, meanings across different branches of law, terms in legal systems from diverse countries, and terms in different languages. These issues led to the development of a classification and subject indexing system which will help answer the major challenges of indexing and classifying law resources in the Research Institute Library at the National Autonomous University of Mexico. Adopting its own classification required interdisciplinary work between law and information organization specialists, constant updating by legal specialists and others beyond the Legal Research Institute; and the sharing of this classification system with other institutions. Now, this classification system is used by important institutions that specialize in law, such as the network of Libraries of the Supreme Court of Justice of the Nation of Mexico. The purpose of this article is to show why and how this law classification and subject system was developed and is continuously being updated by libarians and law scholars in order for it to meet their specific needs.     

Double poling kinematic changes during the course of a long-distance race: effect of performance level

ABSTRACT

We aimed to evaluate the changes in double poling (DP) kinematics due to a long-distance cross-country skiing race in athletes with different performance levels. A total of 100 cross-country skiers, belonging to 10 different performance groups, were filmed on flat terrain 7 and 55 km after the start line, during a 58-km classical race. Cycle velocity, frequency and length decreased from the best to the lower-ranked group, while duty cycle increased (all P <.001). Between track sections, cycle velocity and length decreased, duty cycles increased (all P <.001) while frequency was unaltered (P =.782). Group*section interactions resulted for cycle velocity (P =.005). Considering all the participants together, % change in cycle velocity between sections correlated with % change in length and duty cycle (all P <.001). Thus i) skiers in better groups showed longer and more frequent cycles as well as shorter duty cycles than skiers in slower groups; ii) throughout the race all the groups maintained the same cycle frequency while decreasing cycle velocity and length; iii) better groups showed a lower reduction in cycle velocity. Individually, a low reduction in cycle velocity during the race related to the capacity to maintain long cycles and short duty cycles.     

Identification of critical intensity from a single lactate measure during a 3-min,submaximal cycle-ergometer test

We tested the hypothesis that critical intensity in cycling can be determined from a single delta blood lactate in the third minute of a submaximal cycle ergometer trial. Fourteen healthy young men performed four to six constant-power-output trials on a cycle ergometer to the limit of tolerance. Critical intensity was calculated via a linear model and subsequently validated. Lactate was measured at baseline and at 3 min from exercise onset. Delta lactate was the difference between these measures. Based on individual trials, we obtained the delta lactate–% validated critical intensity relationship and thereafter an estimate of critical intensity was computed. Validated and estimated critical intensity were compared by effects sizes, paired-sample t-test and Bland–Altman analysis. Delta lactate was a linear function of the intensity of exercise, expressed as % validated critical intensity (R² = 0.89). Estimated critical intensity was not different from (d = 0.03, P = 0.98) and highly correlated with (R² = 0.88) validated critical intensity. The bias between measures was 0.03 W (≠0) with a precision of 7 W. The results suggest that critical intensity in cycling can be accurately and precisely determined from delta lactate during a sub-maximal trial and so provides a practical and valid alternative to direct determination.     

Neuromuscular control during stepping down in continuous gait in individuals with and without ankle instability

Abstract

Ankle sprains are a common injury and those affected are at a risk of developing chronic ankle instability (CAI). Complications of an acute sprain include increased risk of re-injury and persistent disability; however, the exact link between ankle sprains and chronic instability has yet to be elucidated. The purpose of this study was to investigate neuromuscular control (including kinematics, kinetics and EMG) during stepping down from a curb, a common yet challenging daily activity, in persons with ankle instability (n = 11), those with a history of ankle sprain without persistent instability, called ankle sprain “copers” (CPRs) (n = 9) and uninjured controls (CTLs) (n = 13). A significant group difference was noted as the CPR group demonstrated increased tibialis anterior activity in both the preparatory (pre-touchdown) and reactive (post-touchdown) phases when compared to healthy and unstable groups (P < 0.05). It follows that the CPR group also demonstrated a significantly less plantar-flexed position at touchdown than the other two groups (P < 0.05). This is a more stable position to load the ankle and this strategy differed from that used by participants with CAI and uninjured CTLs. These findings provide insight into the neuromuscular control strategies of CPRs, which may allow them to more appropriately control ankle stability following sprains.     

Light damage to selected organic materials in display cases: A study of different light sources

The protection of works of art and cultural assets against light-induced aging is vital when planning exhibitions. Newly developed lighting systems render the selection of suitable light sources more difficult, not least in the context of energy–economical systems. This study accordingly examines different lighting systems (fluorescent tubes, halogen lamps, low-voltage metal halide lamps, and LED lamps) in terms of the damage potential they hold for the materials concerned. The changes in color were evaluated using the CIEDE2000 color-difference formula. This study focuses on selected organic materials and shows that changes in color already occur after only a brief exposure time. The color changes induced by the fluorescent tubes were consistently more intense than those induced by the other light sources. The results obtained with the remaining lamps show that the color changes depend more on the material under investigation than on the source used. The changes determined after a relatively short exposure period (five months) vividly demonstrate that exposing sensitive materials to light for longer terms (as is the case during a permanent exhibition) is most definitely a non-viable option.     

Learning by pigeons playing against tit-for-tat in an operant prisoner’s dilemma

Each of four pigeons was exposed to a single random-ratio schedule of reinforcement in which the probability of reinforcement for a peck on either of two keys was 1/25. Reinforcer amounts were determined by an iterated prisoner’s dilemma (IPD) matrix in which the “other player” (a computer) playedtit-for-tat. One key served as thecooperation(C) key; the other served as thedefection(D) key. If a peck was scheduled to be reinforced and the D-key was pecked, the immediate reinforcer of that peck was always higher than it would have been had the C-key been pecked. However, if the C-key was pecked and thefollowing peck was scheduled to be reinforced, reinforcement amount for pecks on either key were higher than they would have been if the previous peck had been on the D-key. Although immediate reinforcement was always higher for D-pecks, the overall reinforcement rate increased linearly with the proportion of C-pecks. C-pecks thus constituted a form of self-control. All the pigeons initially defected with this procedure. However, when feedback signals were introduced that indicated which key had last been pecked,cooperation (relative rate of C-pecks)—hence, self-control—increased for all the pigeons.     

The irony of rigor: ‘no-excuses’ charter schools at the intersections of race and disability

Across the United States, the ‘no-excuses’ charter school movement featuring strict discipline policies and rigorous academic standards has gained popularity among schools serving poor and working-class students of color. In this article, we examine how Black and Latinx parents of students with disabilities¹ negotiated and experienced these charter school practices of rigor, which disciplined, managed, and regulated students’ social differences. Drawing from a yearlong qualitative research study, we examine interviews with Black and Latinx parents who experienced conflict with charter schools and the school lawyers, along with school artifacts we gathered such as parent handbooks and website information. We found parents experienced what we refer to as the ‘irony of rigor:’ the contradictory double-movement through which students of color with disabilities desired inclusion into ‘rigorous’ charter schools which then excluded them using ‘rigor’ as a central feature of student pushout practices. We present the irony of rigor in three interrelated acts: Act I: the lure of rigor (i.e. what drew parents to charter schools); Act II: the body meets rigor (i.e. how schools disciplined and managed student differences); and Act III: the consequences of rigor (i.e., what happened to students and parents while and after experiencing rigorous practices). We contextualize the irony of rigor within the relationship between disability, race, and neoliberalism.