Parasympathetic activity delayed after self-paced exercise

The main purpose of this study was to compare the effect of the constant load and self-paced exercise with similar total work on autonomic control after endurance exercise. Ten physically active men were submitted to (i) a maximal incremental exercise test, (ii) a 4-km cycling time trial (4-km TT), and (iii) a constant workload test with identical total external work performed at 4-km TT. Gas exchange was measured throughout the tests, while blood lactate, heart rate, and heart rate variability (HRV) were measured during the passive recovery. Power output measured at the last lap (i.e. 3600–4000?m) of 4-km TT (316?±?89?W) was statistically higher than power output measured at the end of the constant workload exercise (211?±?42?W). The 4-km TT produced higher values of blood lactate concentration (8.8?±?2.1?mmol?L^?1) than the constant workload test (7.8?±?2.1?mmol?L^?1). The heart rate recovery measured at 60?s (constant workload: 37?±?7?bpm; 4-km TT: 30?±?6) and 120?s (constant workload: 57?±?9?bpm; 4-km TT: 51?±?9?bpm) were higher in the constant workload than in the self-paced exercise. The HRV (i.e. RMSSD30s) was statistically higher in the constant load exercise measured at 120, 420, 450, 480, 540, and 570?s than the self-paced exercise. These findings suggest that the autonomic control responses were dependent of the endurance exercise modalities, with parasympathetic activity being delayed after self-paced exercise, as evidenced by post-exercise heart rate indices.     

Aerobic exercise training performed by parents reduces mice offspring adiposity

The present study aimed to determine the effects of physical training performed by parents on mice offspring adiposity. Male and female parents underwent an aerobic training protocol for 7 weeks. The trained and sedentary parents were allowed to mate and the resultant offspring divided in: S (Offspring from Sedentary Parents), T (Offspring from Trained Parents), ST (Offspring from Sedentary Father and Trained Mother) and TS (Offspring from Trained Father and Sedentary Mother). After weaning, offspring was euthanized, blood collected and samples of mesenteric and inguinal fat pads used to isolate adipocytes for morphologic and histological analyses. Lee index, mesenteric fat pad, sum of visceral fat and total fat weight of female T was reduced in comparison to the other groups (p < 0.05). Periepididymal and sum of visceral fat in male T group was also reduced when compared to the other groups (p < 0.05). The diameter of mesenteric and inguinal adipocytes of T group was smaller compared to all groups comparisons for both sexes (p < 0.05). In summary, exercise training performed by parents reduced visceral offspring adiposity, the diameter of subcutaneous adipocytes and improved metabolic parameters associated to metabolic syndrome.     

Stability of Markov jump systems with quadratic terms and its application to RLC circuits

The paper presents results for the second moment stability of continuous-time Markov jump systems with quadratic terms, aiming for engineering applications. Quadratic terms stem from physical constraints in applications, as in electronic circuits based on resistor (R), inductor (L), and capacitor (C). In the paper, an RLC circuit supplied a load driven by jumps produced by a Markov chain—the RLC circuit used sensors that measured the quadratic of electrical currents and voltages. Our result was then used to design a stabilizing controller for the RLC circuit with measurements based on that quadratic terms. The experimental data confirm the usefulness of our approach.     

Book-Sharing for Parenting and Child Development in South Africa: A Randomized Controlled Trial

This study evaluated the impact of a parenting intervention on children’s cognitive and socioemotional development in a group of caregivers and their 21-to-28-month-old children in a low-income South African township. A randomized controlled trial compared an experimental group (n = 70) receiving training in dialogic book-sharing (8 weekly group sessions) with a wait-list control group (n = 70). They were assessed before the intervention, immediately following it, and at a six month follow-up. The intervention had positive effects on child language and attention, but not behavior problems, prosocial behavior, or theory of mind. Intervention caregivers were less verbally and psychologically harsh, showed more sensitivity and reciprocity and more complex cognitive talk. This program benefitted parenting and child development and holds promise for low-income contexts.     

Research and teaching writing

Reading and Writing - Writing is an essential but complex skill that students must master if they are to take full advantage of educational, occupational, and civic responsibilities. Schools, and...     

The COVID-19 epidemic in Brazil: how statistics education may contribute to unravel the reality behind the charts

Educational Studies in Mathematics - The world is now facing the most severe health, social, and economic event of the last hundred years, which has made the need to acquire statistical thinking to...     

Biomechanics,energetics and coordination during extreme swimming intensity: effect of performance level

The present study aimed to examine how high- and low-speed swimmers organise biomechanical, energetic and coordinative factors throughout extreme intensity swim. Sixteen swimmers (eight high- and eight low-speed) performed, in free condition, 100-m front crawl at maximal intensity and 25, 50 and 75-m bouts (at same pace as the previous 100-m), and 100-m maximal front crawl on the measuring active drag system (MAD-system). A 3D dual-media optoelectronic system was used to assess speed, stroke frequency, stroke length, propelling efficiency and index of coordination (IdC), with power assessed by MAD-system and energy cost by quantifying oxygen consumption plus blood lactate. Both groups presented a similar profile in speed, power output, stroke frequency, stroke length, propelling efficiency and energy cost along the effort, while a distinct coordination profile was observed (F_{(3, 42)} = 3.59, P = 0.04). Speed, power, stroke frequency and propelling efficiency (not significant, only a tendency) were higher in high-speed swimmers, while stroke length and energy cost were similar between groups. Performing at extreme intensity led better level swimmers to achieve superior speed due to higher power and propelling efficiency, with consequent ability to swim at higher stroke frequencies. This imposes specific constraints, resulting in a distinct IdC magnitude and profile between groups.     

Sharing the Stage

Despite the proliferation of research on social media and journalism, only a few studies have analyzed how journalists in Latin America embrace the affordances of social platforms for journalism practice. Based on a survey of 877 Latin American reporters, this article examines the platforms journalists use and how they use them. The broad finding is that, despite the great popularity of Facebook in the region, Twitter is the most important platform for daily newsgathering and journalistic work. Journalists turn to Twitter to find sources and stories, showing an important openness to participatory journalism. Yet, they mistrust information provided from political sources. Our findings show that different regions in Latin America work with social media in different ways, and local journalistic cultures have an impact on these adoptions, especially in the case of Brazil. Further research and implications for the field are discussed.     

Statistical Properties of the K-Index for Detecting Answer Copying

We investigated the statistical properties of the K-index (Holland, 1996) that can be used to detect copying behavior on a test. A simulation study was conducted to investigate the applicability of the K-index for small, medium, and large datasets. Furthermore, the Type I error rate and the detection rate of this index were compared with the copying index, ω (Wollack, 1997). Several approximations were used to calculate the K-index. Results showed that all approximations were able to hold the Type I error rates below the nominal level. Results further showed that using ω resulted in higher detection rates than the K-indices for small and medium sample sizes (100 and 500 simulees).