Dribbling determinants in sub-elite youth soccer players

Dribbling speed in soccer is considered critical to the outcome of the game and can assist in the talent identification process. However, little is known about the biomechanics of this skill. By means of a motion capture system, we aimed to quantitatively investigate the determinants of effective dribbling skill in a group of 10 Under-13 sub-elite players, divided by the median-split technique according to their dribbling test time (faster and slower groups). Foot-ball contacts cadence, centre of mass (CoM), ranges of motion (RoM), velocity and acceleration, as well as stride length, cadence and variability were computed. Hip and knee joint RoMs were also considered. Faster players, as compared to slower players, showed a 30% higher foot-ball cadence (3.0 ± 0.1 vs. 2.3 ± 0.2 contacts · s^?1, P < 0.01); reduced CoM mediolateral (0.91 ± 0.05 vs. 1.14 ± 0.16 m, P < 0.05) and vertical (0.19 ± 0.01 vs. 0.25 ± 0.03 m, P < 0.05) RoMs; higher right stride cadence (+20%, P < 0.05) with lower variability (P < 0.05); reduced hip and knee flexion RoMs (P < 0.05). In conclusion, faster players are able to run with the ball through a shorter path in a more economical way. To effectively develop dribbling skill, coaches are encouraged to design specific practices where high stride frequency and narrow run trajectories are required.     

A METHOD TO STUDY THE EFFECTS OF MEDIA IN THE CLASSROOM

In Sweden radio and television programs for educational purposes are produced by a special unit within Sveriges Radio (SR), but there is also a production unit outside the organization SR producing educational programs, in the first place for adults (TRU). In the near future these two units are to be joined into one. In the Educational Program Department of SR there is a special group concerned with research and development questions. For the time being there are four full‐time posts as researchers, and within the framework of the budget of the program department the research group has it's own budget for research and evaluation of radio and television in instruction. The aim of this internal research ‐‐ exemplified in this paper ‐ is to give producers such experience as can be of value both for the assessment of individual products and for production work in the long run.     

Two-Year-Old Children's Sensitivity to a Parent's Knowledge State When Making Requests

These studies examined whether toddlers take their communicative partners' knowledge states into account when communicating with them. In Study 1 , 16 2-year-old children (mean age 2-7) had to ask a parent for help in retrieving a toy. On each trial, a child was first introduced to a new toy that was then placed in 1 of 2 containers on a high shelf. The parent either witnessed these events along with the child or did not because she or he had left the room or had covered her or his eyes and ears. As predicted, when asking for help in retrieving the toy, children significantly more often named the toy, named its location, and gestured to its location when a parent had not witnessed these events than when she or he had. In Study 2, 16 2-year-old children (mean age 2-3) had to ask a parent for help in retrieving a sticker dropped into 1 of 2 identical containers placed out of reach in the far corners of a table. The parent either witnessed, along with the child, which container the sticker was dropped into or did not because her or his eyes were closed. In their requests for help, young 2-year-old children gestured to the sticker's location significantly more often when the parent did not know its location than when she or he did. The implications of these findings for current characterizations of 2-year-old children's ability to assess the knowledge of others is discussed.     

Blocking in eyelid conditioning: Effect of changing the CS-US interval and introducing an intertriai stimulus

Kamin’s three-stage blocking paradigm was investigated in rabbit eyelid conditioning, Two manipulations were examined. A change in the CS-US interval from Stage 1 to Stage 2 did not attenuate blocking. The introduction of a salient stimulus during the intertriai interval in Stage 2 also failed to attenuate blocking. The first result is not consistent with Kamin’s interpretation of the blocking effect in terms of US surprisingness. The second resuit is inconsistent with a prediction based on the Rescorla-Wagner model.     

Preschool children’s conceptions of water,molecule, and chemistry before and after participating in a playfully dramatized early childhood education activity

The present study reports an empirical investigation into concept formation of young children. Based on interviews conducted before and after participating in a playfully enacted chemistry lesson at a culture center, it is analyzed how 6-year-old children conceptualize water, molecule, and chemistry. Theoretically, the study is informed by Vygotsky’s cultural-historical perspective on concept formation. The empirical data consist of pre- and post-interviews with children and documentation of their participation in the intermediate activity. This documentation is used in the post-interviews as a mutual ground for talking with the children about what they remember and how they understand the activity they participated in and what the activity intended to illustrate. The results are presented in terms of three inductively generated categories: ‘everyday’, ‘experientially-based’, and ‘generalized experiences’ concepts, respectively. The implications of these findings for early childhood chemistry (science) education are discussed.

     

Laboratory medicine in pandemic of COVID-19

After the outbreak in China in the year 2019, severe acute respiratory syndrome Coronavirus 2 (SARS-CoV-2) quickly spread around the world causing a protracted pandemic. Approximately one-third of infections appear to be asymptomatic. Symptomatic disease is characterized primarily by symptoms of respiratory tract infection of varying severity. But Coronavirus Disease 2019 (COVID-19) is much more than an acute respiratory disease because SARS-CoV-2 affects many organs inducing a vast number of symptoms such as cardiovascular, neurological, gastrointestinal, dermatological, with numerous complications. Short and long-term effects of infection, severe ones, and especially mild forms of the disease which affect a huge number of patients need to be further investigated. Laboratory medicine has a crucial role in early diagnosis of the disease, recognition of the patients who need hospital care, and close monitoring of hospitalized patients to timely identify associated clinical complications as well as follow-up of patients with long-term COVID-19.