Is Quality Control Pointless?

Intrinsic to the transition towards, and necessary for the success of digital platforms as a service (at scale) is the notion of human computation. Going beyond ‘the wisdom of the crowd’, human computation is the engine that powers platforms and services that are now ubiquitous like Duolingo and Wikipedia. In spite of increasing research and population interest, several issues remain open and in debate on large-scale human computation projects. Quality control is first among these discussions. We conducted an experiment with three different tasks of varying complexity and five different methods to distinguish and protect against constantly under-performing contributors. We illustrate that minimal quality control is enough to repel constantly under-performing contributors and that this effect is constant across tasks of varying complexity

Genetic variation for selenium content in tall fescue

Selenium is an element necessary for good animal health. No information is available on inheritance of Se concentration in tall fescue (Festuca arundinacea Shreb.). Therefore, the purpose of this investigation was to determine the nature of genetic variation of Se concentration in tall fescue. To accomplish this objective, 15 parental clones were randomly chosen from a broad-based population, and their half-sib (HS) progenies were generated using a polycross mating design. Selenium analysis was determined flourometrically by digesting dried, ground herbage samples in 3:1 HNO3/HCIO4 . Significant genetic variation was observed among HS families in the fall for Se concentration. Heritability, calculated using parent-offspring (PO) regression, gave estimates of 18% for summer and 68% for the fall. Heritability and genetic gain estimates were maximized in the fall, as compared with the summer, largely because of a large environmental component. Genetic gain, expressed as a percentage of the mean of parents, predicted an advance of 1 9 % for fall herbage. Progress in selecting for improved concentrations of Se in the fall in this population of tall fescue is likely

Genetic variation for selenium content in tall fescue

Selenium is an element necessary for good animal health. No information is available on inheritance of Se concentration in tall fescue (Festuca arundinacea Shreb.). Therefore, the purpose of this investigation was to determine the nature of genetic variation of Se concentration in tall fescue. To accomplish this objective, 15 parental clones were randomly chosen from a broad-based population, and their half-sib (HS) progenies were generated using a polycross mating design. Selenium analysis was determined flourometrically by digesting dried, ground herbage samples in 3:1 HNO3/HCIO4 . Significant genetic variation was observed among HS families in the fall for Se concentration. Heritability, calculated using parent-offspring (PO) regression, gave estimates of 18% for summer and 68% for the fall. Heritability and genetic gain estimates were maximized in the fall, as compared with the summer, largely because of a large environmental component. Genetic gain, expressed as a percentage of the mean of parents, predicted an advance of 1 9 % for fall herbage. Progress in selecting for improved concentrations of Se in the fall in this population of tall fescue is likely