Common single-nucleotide polymorphisms (SNPs) are predicted to collectively explain 40–50% of phenotypic variation in human height, but identifying the specific variants and associated regions requires huge sample sizes1. Here, using data from a genome-wide association study of 5.4 million individuals of diverse ancestries, we show that 12,111 independent SNPs that are significantly associated with height account for nearly all of the common SNP-based heritability. These SNPs are clustered within 7,209 non-overlapping genomic segments with a mean size of around 90 kb, covering about 21% of the genome. The density of independent associations varies across the genome and the regions of increased density are enriched for biologically relevant genes. In out-of-sample estimation and prediction, the 12,111 SNPs (or all SNPs in the HapMap 3 panel2) account for 40% (45%) of phenotypic variance in populations of European ancestry but only around 10–20% (14–24%) in populations of other ancestries. Effect sizes, associated regions and gene prioritization are similar across ancestries, indicating that reduced prediction accuracy is likely to be explained by linkage disequilibrium and differences in allele frequency within associated regions. Finally, we show that the relevant biological pathways are detectable with smaller sample sizes than are needed to implicate causal genes and variants. Overall, this study provides a comprehensive map of specific genomic regions that contain the vast majority of common height-associated variants. Although this map is saturated for populations of European ancestry, further research is needed to achieve equivalent saturation in other ancestries.

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Goal-directed actions are instrumental behaviors whose performance depends on the organism’s knowledge of the reinforcing outcome’s value. In contrast, habits are instrumental behaviors that are insensitive to the outcome’s current value. Although habits in everyday life are typically controlled by stimuli that occasion them, most research has studied habits using free-operant procedures in which no discrete stimuli are present to occasion the response. We therefore studied habit learning when rats were reinforced for lever pressing on a random interval 30-s schedule in the presence of a discriminative stimulus (S), but not in its absence. In Experiment 1, devaluing the reinforcer with taste aversion conditioning weakened instrumental responding in a 30-s S after 4, 22, and 66 sessions of instrumental training. Even extensive practice thus produced goal-directed action, not habit. Experiments 2 and 3 contrastingly found habit when the duration of S was increased from 30 s to 8 min. Experiment 4 then found habit with the 30-s S when it always contained a reinforcer; goal-directed action was maintained when reinforcers were earned at the same rate, but occurred in only 50% of Ss (as in the previous experiments). The results challenge the view that habits are an inevitable consequence of repeated reinforcement (as in the Law of Effect), and instead suggest that discriminated habits develop when the reinforcer becomes predictable. Under those conditions, organisms may pay less attention to their behavior, much as they pay less attention to signals associated with predicted reinforcers in Pavlovian conditioning.

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BackgroundAbdominoplasty, with or without liposuction, is among the most frequently performed aesthetic procedures. Its main objective is to improve the body contour by means of excising redundant skin and fat tissue. Although abdominoplasty is considered a safe procedure with high satisfaction rates, intraoperative and postoperative complications can become a challenge for the surgical team. The aim of this article is to offer a synopsis of the most common complications arising after abdominoplasty, along with evidence-based guidelines about how to prevent and treat them.MethodsA systematic MEDLINE search strategy was designed using appropriate Medical Subject Headings (MeSH) terms, and references were scanned for further relevant articles.ResultsAccording to the published case series, local complications are considerably more common than complications with systemic repercussions. Approximately 10% to 20% of patients suffer a local complication following abdominoplasty, while fewer than 1% suffer a systemic complication. Prevention and management strategies are critically discussed for complications including seroma, haematoma, infection, skin necrosis, suture extrusions, hypertrophic scars, neurological symptoms, umbilical anomalies, deep venous thrombosis and pulmonary thromboembolism, respiratory distress, and death.ConclusionsThe complications of abdominoplasty vary in severity and in the impact they have on the aesthetic outcomes. Recommendations for prevention and management are based on various levels of evidence, with a risk of observer bias. However, most complications can be treated appropriately following the current standards, with satisfactory results.