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The Efficacy of HIIT and HIRT in Older Adults
No full textModerate intensity continuous exercise (MICE) improves aerobic and functional fitness and prevents chronic disease and premature morbidity. Aerobic and functional fitness are validated clinical indicators of chronic disease risk. High intensity interval training (HIIT) is a time efficient and safe alternative to MICE that has positive effects on some chronic diseases and risk in younger healthy populations. Limited research has investigated HIIT in older, at-risk populations; and the health benefits of including resistance traininginto HIIT approaches (HIRT) is even more limited in older, at-risk adults. The purpose of this research was to determine the aerobic and functional fitness efficacy of HIIT and HIRT exercise interventions compared to MICE in older adults at-risk for chronic disease.
Forty-eight adults (≥65 years) were recruited and randomized into three 8-week exercise intervention groups: MICE (active control), HIIT, and HIRT. Aerobic (VO2max) and functional fitness (functional movement screen, FMS; timed-up-and-go, TUG; floor transfer time, FTT) were measured at baseline and after 8-weeks. VO2max improved similarly in all groups (HIIT 2.2±0.3; HIRT=3.5±0.7. MICE 2.1±0.5 ml/kg/min, P\u3c0.01). Both high-intensity groups improved in FTT (HIRT=17%, P\u3c0.01; HIIT=12%, P\u3c0.05) and FMS (HIRT=17%, HIIT =10%,P\u3c0.01). Only HIRT improved in TUG (10.6%) and balance (9%). No injuries or adverse events occurred in any group. HIRT and HITT are as safe and efficacious as MICE in older adults for improving aerobic and functional fitness. HIRT appears to elicit additional functional fitness benefits, but both high-intensity approaches are safe and effective alternatives for older adults’ with or at-risk for developing chronic disease
Childhood Poverty and Its Effects on the Brain: Physiological and Functional Implications
No full textOne out of every five American children lives below the federal poverty line. Considering that poverty is deemed one of the most influential risk factors for poor developmental outcomes, it is critical to understand what effect poverty has on the developing brain and how those brain changes affect a child’s life. Poverty is chiefly defined by having a low socioeconomic status (SES), but a low SES is often accompanied by other influencers, such as nutrition and mental stimulation, termed poverty co-factors. Other poverty co-factors include, but are not limited to, maternal stress and malnutrition, environmental toxins, parental nurturance, and education.
A low SES and accompanying poverty co-factors influence changes in the brain, including both the type and rate of change. Variances have been noted in the frontal lobe, prefrontal cortex, amygdala, hippocampus, and the white and grey matter size and ratios. Neurotransmitter and hormone modifications have also been observed. These brain changes have long-reaching impacts, affecting educational and intellectual attainment, emotional processing, and risk of mental illness.
As knowledge regarding poverty-driven brain changes increases, more possible intervention strategies are being developed. These strategies center on parental involvement and mental and verbal stimulation. The achievement discrepancies noticed between children raised below the poverty line and children raised above it likely contribute to the continuation of intergenerational poverty. Further research and information regarding poverty and how it affects the developing brain contribute to developing target strategies to ameliorate the effects of childhood poverty
On the distance and distance signless Laplacian eigenvalues of graphs and the smallest Gersgorin disc
No full textThe \emph{distance matrix} of a simple connected graph is , where is the distance between the th and th vertices of . The \emph{distance signless Laplacian matrix} of the graph is , where is a diagonal matrix whose th diagonal entry is the transmission of the vertex in . In this paper, first, upper and lower bounds for the spectral radius of a nonnegative matrix are constructed. Applying this result, upper and lower bounds for the distance and distance signless Laplacian spectral radius of graphs are given, and the extremal graphs for these bounds are obtained. Also, upper bounds for the modulus of all distance (respectively, distance signless Laplacian) eigenvalues other than the distance (respectively, distance signless Laplacian) spectral radius of graphs are given. These bounds are probably first of their kind as the authors do not find in the literature any bound for these eigenvalues. Finally, for some classes of graphs, it is shown that all distance (respectively, distance signless Laplacian) eigenvalues other than the distance (respectively, distance signless Laplacian) spectral radius lie in the smallest Ger\^sgorin disc of the distance (respectively, distance signless Laplacian) matrix
Average Mixing Matrix of Trees
No full textThe rank of the average mixing matrix of trees with all eigenvalues distinct, is investigated. The rank of the average mixing matrix of a tree on n vertices with n distinct eigenvalues is bounded above by ⌈n/2⌉. Computations on trees up to 20 vertices suggest that the rank attains this upper bound most of the time. An infinite family of trees whose average mixing matrices have ranks which are bounded away from this upper bound, is given. A lower bound on the rank of the average mixing matrix of a tree, is also given