Body composition assessment methods are dependent on their underlying principles, and assumptions of each method may be affected by age and sex. This study compared an abdominal circumference-focused ...method of percent body fat estimation (AC %BF) to a criterion method of dual-energy x-ray absorptiometry (DXA), and a comparative assessment with bioelectrical impedance (BIA), in younger (≤30 years) and older (>age 30 years) physically fit (meeting/exceeding annual US Marine Corps fitness testing requirements) men and women.
Fit healthy US Marines (430 men, 179 women; 18-57 years) were assessed for body composition by DXA (iDXA, GE Lunar), anthropometry, and BIA (Quantum IV, RJL Systems).
Compared to DXA %BF, male AC %BF underestimated for both ≤30 and >30 years age groups (bias, -2.6 ± 3.7 and -2.5 ± 3.7%); while female AC %BF overestimated for both ≤30 and >30 years age groups (2.3 ± 4.3 and 1.3 ± 4.8%). On an individual basis, lean men and women were overestimated and higher %BF individuals were underestimated. Predictions from BIA were more accurate and reflected less relationship to adiposity for each age and sex group (males: ≤30, 0.4 ± 3.2, >30 years, -0.5 ± 3.5; women: ≤30, 1.4 ± 3.1, >30 years, 0.0 ± 3.3). Total body water (hydration) and bone mineral content (BMC) as a proportion of fat-free mass (FFM) remained consistent across the age range; however, women had a higher proportion of %BMC/FFM than men. Older men and women (>age 30 years) were larger and carried more fat but had similar FFM compared to younger men and women.
The AC %BF provides a field expedient method for the US Marine Corps to classify individuals for obesity prevention, but does not provide research-grade quantitative body composition data.
Suppose that a connected graph G has at least one cycle and let g be the length of the shortest cycle in G, which is called the girth of G. In this paper, we consider relationship between the girth ...of G and the number of negative eigenvalues (including multiplicities) of the adjacency matrix of G, known as negative inertia index of G and denoted by i−(G). We prove that i−(G)≥⌈g2⌉−1. Furthermore, all extremal graphs corresponding to i−(G)=⌈g2⌉−1 and i−(G)=⌈g2⌉ are characterized, respectively.
El Sahili conjectured that every oriented n-path, where n≥8, is contained in every n-chromatic digraph. This conjecture was confirmed by Gallai–Hasse–Roy–Vitaver’s theorem for directed paths and by ...Addario-Berry et al. for oriented paths with two blocks. A block of an oriented path is a maximal directed subpath. El Joubbeh showed that every (4n−4)-chromatic digraph contains every oriented n-path with three blocks. For oriented paths with more than three blocks, Addario-Berry et al. established that every oriented n-tree, and hence every oriented n-path with any number of blocks, is contained in every (n22−n2+1)-chromatic digraph. This paper proposes an improvement to the bound on the chromatic number for digraphs that must include all paths consisting of four blocks. In fact, we extend El Joubbeh’s bound on the chromatic number from (4n−4) for digraphs that should contain every n-path with three blocks to (4n−2) for digraphs that should be contain every n-path with four blocks. This bound surpasses the one provided by Addario-Berry et al. Furthermore, we show that every oriented n-path with t blocks, t≥4, is contained in every (4r(t)n+q(t))-chromatic digraph where r(t)=log2(t−1) and q(t)=−2078r(t)−1+67. Finally, the paper highlights an improvement in the bound of Addario-Berry et al. for n-paths with t blocks, where t≤n−12+1.
A bi-coset graph Γ(G;H,K) is a bipartite graph with the two vertex sets consisting of the cosets of subgroups H,K of a group G, and the adjacency determined by non-empty intersection. Bi-coset graphs ...constitute a classical object of algebraic graph theory and have been studied in various contexts (often with regard to their symmetries). In this paper, bi-coset graphs are revisited with the aim of using them in connection with the Cage Problem, the problem of finding a smallest k-regular graph of girth g, and with its generalization, the problem of finding a smallest biregular graph of girth g with vertices of degrees m,n. The girth of a bi-coset graph is shown to be related to the existence of special alternating sequences of elements from H and K, and k-regular bi-coset graphs of arbitrary large girths are shown to exist for all k≥2. Bi-coset graphs are shown to be particularly suitable for constructions of bipartite biregular graphs which are biregular graphs in which each of the two sets making the graph bipartite consists of vertices of the same degree. A few bipartite biregular bi-coset graphs found in the paper are shown to be of the smallest order among all bipartite biregular graphs with the same parameters. Interestingly, one of our constructions starts from prime pairs of the form p, 6p+1.
The cultivation of elite latex-timber clones that exhibit both enhanced NR and wood production has become a key objective in current Hevea brasiliensis breeding programs. The girth and dry rubber ...yield (DRY) are two crucial indicators for evaluating the latex-timber characteristics of Hevea trees. However, the quantitative trait locus (QTL) and candidate genes identified for these traits are still limited. Here, a genome-wide association study (GWAS) was performed in a Whickham germplasm offspring to identify genetic variants associated with girth and DRY. Girth and DRY phenotypes were measured for three consecutive years. Meanwhile, a total of 7835,736 high-confidence SNPs were identified from 218 Hevea accessions. Remarkably, the population exhibited a high level of genetic diversity, coupled with a rapid decline in linkage disequilibrium, and was roughly grouped into three subgroups by population structure analysis. A total of 17 and 76 SNPs, respectively, correlated significantly with girth DRY, and corresponded to 31 and 284candidate genes for girth and DRY. To further assess the candidates, gene expression analyses were performed separately on four types of Hevea tree tissues and two distinct groups exhibiting notable girth or DRY phenotypic differences. Eventually, a cullin protein and an iridoid oxidase protein were identified as prospective girth regulators, whereas two chloroplast thylakoid membrane proteins and an auxin-repressed protein were implicated in shaping the performance of DRY. These findings contribute to a deeper understanding of the genetic foundations of girth and DRY, as well as molecular-assisted breeding of latex-timber rubber clones.
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•Genome-wide association study on 218 offspring accessions of Hevea Wickham germplasm to identify girth and rubber yield QTLs.•Substantial genetic diversity observed in this progeny population.•17 and 76 significant SNPs associated with girth and rubber yield, respectively.•The cullin and iridoid oxidase identified as promising candidates for regulating girth development.•The chloroplast thylakoid membrane and auxin-repressed proteins identified as candidates affecting rubber yield.
In 2015, Dankelmann and Bau proved that for every connected bridgeless graph G of order n and minimum degree δ there is an orientation of diameter at most 11nδ+1+9. In 2016, Surmacs reduced this ...bound to 7nδ+1. In this paper, we consider the girth of a graph g and show that for any ε>0 there is a bound of the form (2g+ε)nh(δ,g)+O(g4ε2), where h(δ,g) is a polynomial. Fixing 0<ε<1, g, and δ gives an improvement on the result by Surmacs for sufficiently large n.
The modelling of interconnection networks by graphs motivated the study of several extremal problems that involve well known parameters of a graph (degree, diameter, girth and order) and optimising ...one of the parameters given restrictions on some of the others. Here we focus on bipartite Moore graphs, that is, bipartite graphs attaining the optimum order, fixed either the degree/diameter or degree/girth. The fact that there are very few bipartite Moore graphs suggests the relaxation of some of the constraints implied by the bipartite Moore bound. First we deal with local bipartite Moore graphs. We find in some cases those local bipartite Moore graphs with local girths as close as possible to the local girths given by a bipartite Moore graph. Second, we construct a family of
(
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-bipartite graphs of order
2
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and diameter 3, for
q
a power of prime. These graphs attain the record value for
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and improve the values for
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and
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