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OBJECTIVE: To investigate methodological aspects in body fat (BF) measurements in 7-to-10-year-old children. STUDY DESIGN: Systematic review of the literature. METHODS: The studies were chosen from the PubMed and Scielo databases according to a protocol that defined: inclusion criteria; a search and quality-assessment strategy; and information extraction. RESULTS: 27 studies published from 2004 to 2014 were included. The literature describes skinfold measurements and dual energy X-ray absorptiometry (DEXA) as being the reference methods most widely used in the assessment of the ability of methods to identify BF. The most commonly-used statistical analyses were the Pearson correlation coefficient, and sensitivity and specificity performance analyses. The comparison between the tested methods and the references showed that body mass index (BMI) and waist circumference (WC) are strongly correlated to BF as calculated by bioelectrical impedance or skinfolds, and that there is a moderate positive correlation with percent body fat as calculated by DEXA, air-displacement plethysmography (ADP) or isotope dilution. There was a moderate positive correlation between waist-to-height ratio (WHtR) and BF, as estimated by ADP and skinfolds. Performance studies suggest that BMI and WC are very specific but less sensitive methods. CONCLUSIONS: The results of this systematic review show favourable evidence for the use of anthropometric indicators - above all BMI and WC- in the measurement of BF, when more accurate techniques such as DEXA and ADP are not feasible. They also demonstrate features that make them advantageous for epidemiological studies in a child population, since they are easy and safe to obtain and well tolerated by the children.

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Primary familial brain calcification (PFBC) is identified by mineralization of the basal ganglia and other brain regions in the absence of known causes. The condition is often inherited in an autosomal dominant pattern and can manifest itself clinically with neuropsychiatric symptoms such as Parkinsonism, headaches, psychosis, and mood swings. Mutations in the SLC20A2 gene account for ~40% of inherited cases, and this gene encodes an inorganic phosphate transporter (PiT-2), a transmembrane protein associated with Pi homeostasis. The p.Y386X mutation in SLC20A2 was identified in a patient who presented migraines, brain calcification, and mild but chronic hypovitaminosis D. SLC20A2 c.1158C > G single-nucleotide heterozygous mutation results in a premature stop codon and a putative truncated protein of 385 amino acids. Proband parents do not present the mutation, which is also not present in major public SNP databases, suggesting a de novo sporadic trait. This study describes for the first time a de novo SLC20A2 mutation in a PFBC patient with migraine and mild hypovitaminosis D. This data further reinforces the pathogenic role of SLC20A2 mutations as causal factors in PFBC physiopathology.

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We study numerically correlation and response functions in nonequilibrium driven vortex lattices with random pinning. From a generalized fluctuation-dissipation relation, we calculate an effective transverse temperature in the fluid moving phase. We find that the effective temperature decreases with increasing driving force and becomes equal to the equilibrium melting temperature when the dynamic transverse freezing occurs. We also discuss how the effective temperature can be measured experimentally from a generalized Kubo formula.

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We find mode-locking steps in simulated current-voltage characteristics of ac-driven vortex lattices with random pinning. For low frequencies there is mode locking above a finite ac force amplitude, while for large frequencies there is mode locking for any small ac force. This is correlated with the nature of temporal order in the different regimes in the absence of ac drive. The mode-locked state is a frozen solid pinned in the moving reference of frame, and the depinning from the step shows plastic flow and hysteresis.