Recent Progress in Shearlet Theory: Systematic Construction of Shearlet Dilation Groups, Characterization of Wavefront Sets, and New Embeddings

The class of generalized shearlet dilation groups has recently been developed to allow the unified treatment of various shearlet groups and associated shearlet transforms that had previously been studied on a case-by-case basis. We consider several aspects of these groups: First, their systematic construction from associative algebras, secondly, their suitability for the characterization of wavefront sets, and finally, the question of constructing embeddings into the symplectic group in a way that intertwines the quasi-regular representation with the metaplectic one. For all questions, it is possible to treat the full class of generalized shearlet groups in a comprehensive and unified way, thus generalizing known results to an infinity of new cases. Our presentation emphasizes the interplay between the algebraic structure underlying the construction of the shearlet dilation groups, the geometric properties of the dual action, and the analytic properties of the associated shearlet transforms.Comment: 28 page

Genetic predisposition influences plasma lipids of participants on habitual diet, but not the response to reductions in dietary intake of saturated fatty acids

Objective: SNPs identified from genome wide association studies associate with lipid risk markers of cardiovascular disease. This study investigated whether these SNPs altered the plasma lipid response to diet in the ‘RISCK’ study cohort. Methods: Participants (n = 490) from a dietary intervention to lower saturated fat by replacement with carbohydrate or monounsaturated fat, were genotyped for 39 lipid-associated SNPs. The association of each individual SNP, and of the SNPs combined (using genetic predisposition scores), with plasma lipid concentrations was assessed at baseline, and on change in response to 24 weeks on diets. Results: The associations between SNPs and lipid concentrations were directionally consistent with previous findings. The genetic predisposition scores were associated with higher baseline concentrations of plasma total(P = 0.02) and LDL (P = 0.002) cholesterol, triglycerides (P = 0.001) and apolipoprotein B (P = 0.004), and with lower baseline concentrations of HDL cholesterol (P < 0.001) and apolipoprotein A-I (P < 0.001). None of the SNPs showed significant association with the reduction of plasma lipids in response to the dietary interventions and there was no evidence of diet-gene interactions. Conclusion: Results from this exploratory study have shown that increased genetic predisposition was associated with an unfavourable plasma lipid profile at baseline, but did not influence the improvement in lipid profiles by the low-saturated-fat diets

Reference centile curves for screening body mass index and body postural stability in football players aged 8-18 years

Introduction and purpose: Since birth, children grow up in terms of height and body weight, and subsequently in terms of the maturation of the nervous, endocrine, muscular, and cardiovascular systems. These adaptations lead to alterations in neuromuscular performances (3). The increase of body mass index (BMI) can cause a reduction in the postural stability and then increase the risk of falls, particularly when combined with low muscular mass which can generate biomechanical failure of muscular responses and loss of stability mechanisms (2). The aim of this study was to analyse the body mass index (BMI) and body postural stability (BPS) in football players across childhood and adolescence, thus developing reference centile curves, and to investigate their relationship. Methods: 512 males from 8 to 18 years were recruited from Italian football teams. It was performed a cross-sectional study. BMI was calculated measuring height and weight [body mass (kg) / height (m2)]. BPS were taken by means of a Libra seesaw balance board. Reference centile curves were created by lambda-mu-sigma (LMS) method. To assess the difference among ages, Kruskal Wallis test was performed. The correlation between BMI and BPS was evaluated by Pearson correlation coefficient controlled by age (partial correlation). In addition, a stepwise multiple regression analysis was used to determine the effect of age and BMI on BPS, and the effect of age and BPS on BMI. Finally, Pearson correlation coefficient or Sperman Rho were performed in order to detect the correlation between BMI and BPS in each age group. The assumption of normal data distribution was verified by Shapiro-Wilks\u2019 Normality test. Results: Significant improvement in BMI (\u3c72(1,10)=106.383, p0.251, p<0.05) except for football players of 11, 14, and 15 years old. Conclusion: The football players increase BMI and improve their BPS during the growth. The reference centile curves provided in this study could help trainers to assess the levels of their football players. Previous studies found that the accumulation of fat tissue can reduce postural stability and contribute towards falls (1). Accordingly, we found a direct relationship between BPS and BMI across childhood and adolescence. The lower is the BMI, the better is the body postural stability during the growth, because high BMI demands more neuromuscular control to maintain postural stability (1). However, our results showed improvements on BMI and BPS were mostly affected by the body development during growth and barely affected by their relationship. A greater limitation of this investigation is that this study have a cross sectional design. Future longitudinal study is needed to better investigate this topic. References 1. Greve, J., Alonso, A., Bordini, A.C.P.G., & Camanho, G.L.. Correlation between Body Mass Index and Postural Balance. Clinics 62, 717\u201320 (2007). 2. Maffiuletti, N.A., Agosti, F., Proietti, M., Riva, D., Resnik, M., Lafortuna, C.L., & Sartorio, A. Postural Instability of Extremely Obese Individuals Improves after a Body Weight Reduction Program Entailing Specific Balance Training. Journal of Endocrinological Investigation 28, 2\u20137 (2005). 3. Roemmich, J. N. & Rogol, A. D. Physiology of growth and development. Its relationship to performance in the young athlete. Clinics in Sports Medicine 14, 483\u2013502 (1995)

Maximal isometric force and forearm muscle cross-sectional area in prepubertal soccer players

Maximal isometric handgrip force (F), forearm cross-sectional area (CSA) and the ratio F/CSA (stress) were measured in 41 prepubertal soccer players F and CSA showed a linear relationship with agel as were linear the relationships between weight and height vs age. Childrens showed a significantly lower (p&lt;0.001) stress value than adults. Stress increases progressively with age to reach a value similar to that of adult peoples at about 12 years of age. From the literature data the stress seems to be independent of sex and age between 12 and 60 years of age, while in the pennate muscles stress may be modified by resistance training. In young and old peoples stress seems to be modifiable by different levels of maturity or involution of the muscular tissue, depending on some hormonal, trophyc and neurological factors

Relationship between vertical jump and body postural stability in males and females aged 6-18 years

Introduction: Body postural stability and vertical jump can be influenced by age, as well as anthropometric characteristics and sport participation (Jallai et al., 2011). However, uncertain correlation between BPS and vertical jump height have also been reported. In prepubertal children and adolescents no correlations have been found (Granacher and Gollhofer, 2011), albeit good correlations have been reported in young soccer players (Gualtieri et al., 2009). Thus, the aim of this study was to investigate the relationship between body postural stability and vertical jump height in males and females aged 6-18 years. Methods: Nine hundred and eighty-five subjects from 6 to 18 years took part in this study (699 males and 286 females). Body postural stability and vertical jump height were measured by balance test (BPS; Libra board, Easytech, Prato, Italia) and countermovement jump test (CMJ; Optojump, Microgate, Bolzano, Italia), respectively. To assess the interaction between sex and among ages, two-way multivariate analysis of variance (MANOVA) was performed. If Wilk\u2019s lambda achieved statistical significance, the univariate test (ANOVA) was examined for the individual dependent variables applying a Bonferroni\u2019s adjustment of alpha. The partial eta squared (part eta2) was used to detect the magnitude of the differences. In order to detect the relationship between BPS and CMJ in males and females, the Pearson Correlation Coefficient controlled by age (partial correlation) was computed. Results: The two-way MANOVA showed statistical interaction among age and between sex (Wilks lambda=0.96; F=2.35; p=.04; partial eta2=0.20). Univariate analysis of variance found a statistical interaction only for CMJ (F=2.35; p=.04; partial eta2=0.20). Partial correlation showed statistical significance in both males (r=-0.410, p<0.001) and females (r=-0.169, p=0.01). Discussion: The difference between sex and age in CMJ could be explained by the different maturation of nervous, endocrine, muscular, and cardiovascular systems during growth (Roemmich and Rogol, 1995). However, these adaptations did not affect the BPS between sex. The correlation found between BPS and CMJ, especially in males, suggests that training one of these abilities could affect the other one. References: Granacher U, Gollhofer A. (2011). J Strength Cond, 25(6), 1718\u20131725. Gualtieri D, Cattaneo A, Sarcinella R, Cimadoro G, Alberti G. (2009). Sport Sci Health, 3(3), 73\u201376. Jallai T, Ereline J, Kums T, Aibast H, Gapeyeva H, P\ue4\ue4suke M. (2011). AKUT, 17, 89\u201398. Roemmich JN, Rogol AD. (1995). Clinics in Sports Medicine, 14(3), 483\u2013502

Energetic expenditure during in-field rehabilitation after ACL reconstruction in soccer players

In-field rehabilitation (IFR) consists on sport specific exercises and drills performed in a playing field under supervision of rehabilitative personnel aimed to regain the fitness level required for training with the team. During IFR functional recovery is attained by progressively increasing loads, so IFR may be subdivided into 5 phases characterized by specific drills performed at different intensity. PURPOSE: To determine the energetic expenditure of soccer players during IFR after Anterior Cruciate Ligament (ACL) reconstruction. METHODS: 17 male soccer players (30.2 \ub1 8.6yrs; 76.9 \ub1 8.7 kg; 180 \ub1 3 cm) of different levels started IFR 129 \ub1 39 days after ACL surgical reconstruction. IFR consisted on 3 sessions a week (90 minutes each) for 4 weeks. Energetic expenditure (EE, kcal/h) was assessed by a multi-sensor device recording physiological body signals (skin temperature, near body temperature/heat flux, galvanic skin resistance, 2 accelerometers; Armband, Body Media, Pittsburg, PA) worn on the lateral head of the right triceps brachii. This device allows also to calculate the Metabolic Equivalents (METs) and the number of steps. RESULTS: EE, METs and number of steps/hours (means \ub1 SD) for each of the 5 phases of IFR are showed in the table. TU1 CONCLUSIONS: The energetic expenditure and the number of steps/hours increased significantly (P &lt; 0.001) over the 5 phases as a result of the increased functional demand of the last period of rehabilitation. EE in the 5th phase was lower (-30%) than that reported in the literature for healthy soccer players during competitions. The injured player may return to his team after attaining the complete functional recovery of the injured limb, considering also the EE at the end of the rehabilitation