Synthesis and multistate characterization of bis-flavylium dications – symmetric resorcinol- and phloroglucinol-type derivatives as stochastic systems

Two as one! Full kinetic and thermodynamic characterization of two easy-to-prepare bis-flavylium multistate systems showed stochastic behavior, thus revealing lack of interactions between flavylium moieties.

Perceptual responses in free vs. constant pace exercise

The purpose of the present investigation was to study the influence of free versus constant pace on perceived exertion (RPE) and estimated time Limit (ETL). Ten athletes performed a graded test aimed to determine maximal oxygen uptake (VO2max) and the velocity associated with VO2max (vVO2max), a constant run to exhaustion at 90 % vVO2max to determine the time and distance to exhaustion at this relative velocity, a free paced run over the distance to exhaustion set by the time to exhaustion at 90 % vVO2max. Oxygen uptake and velocity during constant pace and free pace runs were both averaged throughout the entire period of exercise and without the last lap. The results did not show any significant effect of free versus constant pace on RPE and ETL. Averaged oxygen uptake between free and constant pace runs was not significantly different, whereas averaged vVO2max, % vVO2max and time to exhaustion was significantly higher for free pace runs only for the entire exercise. Consequently, compared to the constant pace run, the free pace one only allowed athletes to finish the run by a sprint which was effective in increasing performance, but not to perceive the free pacing run as being less strenuous than the constant pace one.

[Diagnosing eating disorders: presentation of a new diagnostic test and an initial epidemiological study of eating disorders in adolescents]

Precise diagnosis of eating disorders has long been problematic. First off, although the DSM IV provides clear criteria, these are applicable to a very narrow range of disorders. Subclinical disorders, although well defined in the literature, are difficult to diagnose as no tool has been previously available. These subclinical disorders are particularly important if one considers that they are often precursors to more serious and life-threatening eating disorders. In addition, choice of diagnostic tool for eating disorders has also long been the cause of difficulty for both researchers and clinicians. Although interviews are favored for their in-depth approach, they are sometimes difficult to implement and often too long and costly to use on a regular basis. Most available questionnaires are limited by their approach to one or two diagnostic categories, and again, until now, no tool has fully addressed the issue of subclinical disorders. The goal of this work was to translate and use a new questionnaire, The Questionnaire for Eating Disorders (Q-EDD), which was developed in the United States and based on both DSM IV criteria as well as carefully developed subclinical disorder criteria. The Q-EDD can identify the major eating disorder categories while at the same time distinguishing between different qualities in each (for example restricting versus compensatory anorexia). Moreover, the Q-EDD can identify several subclinical disorder categories, providing useful insight into potentially dangerous evolution of these disorders. In collaboration with one of the original authors, the questionnaire was translated into French with careful attention to DSM IV criteria in order to preserve its original validity. The questionnaire was read by several professionals in psychology as well as lay people to assure its face validity and ease of use. Once the questionnaire was adequately translated and corrected, it was used for an epidemiological study with a large sample of adolescents and young adults (n=1 001) from several Junior High and High Schools in the greater metropolitan area of Toulouse, France. The schools were located in a variety of neighborhoods and represented a wide range of population, some of them being more academic oriented, others being more oriented towards practical training. The population was composed of 703 females and 298 males, with an average age of 17.06 years. In addition, the population included several different ethnic categories, all of which are similarly represented in the general French population. The results from the Q-EDD showed levels of various clinical disorders to replicate data from previous epidemiological studies with 1.5% of the population suffering from a serious clinical DSM IV disorder; 7.9% suffering from DSM IV disorders NOS; and 20.9% suffering subclinical disorders. In addition to this finding of 30% of the population with an eating disorder, it was noted that a large number of these young people fell into the severe underweight and low weight categories. Indeed, nearly 10% of this group were within the weight criteria for anorexia, despite the fact that they did not meet the other criteria. This finding seemed to warrant additional investigation, and as a result, a different cut-off for severe underweight was established using literature references; this cut-off was set at the 10(th) percentile for BMI based on age. Yet, even with this new cut-off, 6% of this population still met a severe underweight criteria suggestive of anorexic pathology. These results led to the formulation of 2 hypotheses to explain this finding, the first of which examines morphological differences, the second of which suggests cultural differences in terms of eating habits and diet. The French version of the Q-EDD appears to follow the psychometric properties of the original version, moreover it provides useful and rich data regarding eating disorders in a format that is simple and efficient.

Effect of free versus constant pace on performance and oxygen kinetics in running

PURPOSE

This study tested the hypothesis that free versus constant pace enhanced the performance (i.e., distance run) in suprathreshold runs between 90 and 105% of the velocity associated with the maximal oxygen consumption determined in an incremental test (v.VO(2max)). Moreover, we hypothesized that variable pace could decrease the slow phase of oxygen kinetics by small spontaneous recoveries during the same distance run at an average velocity.

METHOD

Eleven long-distance runners performed nine track runs performed until exhaustion. Following an incremental test to determine v.VO(2max), the runners performed, in a random order, four constant-velocity runs at 90, 95, 100, and 105% of v.VO(2max) to determine the time to exhaustion (tlim90, tlim95, tlim100, and tlim105) and the distance limit at 90, 95, 100 and 105% of v.VO(2max) (dlim90, dlim95, dlim100, and dlim105). Finally, they performed the distance limit determined in the constant velocity runs but at variable velocity according to their spontaneous choice.

RESULTS

The coefficient of variation of velocity (in percent of the average velocity) was small and not significantly different between the four free pace dlim (4.2 +/- 1.3%, 4.8 +/- 2.4%, 3.6 +/- 1.1%, and 4.6 +/- 1.9% for dlim90, dlim95, dlim100, and dlim105, respectively; P = 0.40). Performances were not improved by a variable pace excepted for the dlim at 105% v.VO(2max) (4.96 +/- 0.6 m.s-1 vs 4.86 +/- 0.5 m.s-1, P = 0.04). Oxygen kinetics and the volume of oxygen consumed were not modified by this (low) variation in velocity.

CONCLUSION

These results indicate that for long-distance runners, variable pace modifies neither performance nor the oxygen kinetics in all-out suprathreshold runs.