The tri-flow adaptiveness of codes in major evolutionary transitions.

Life codes increase in both number and variety with biological complexity. Although our knowledge of codes is constantly expanding, the evolutionary progression of organic, neural, and cultural codes in response to selection pressure remains poorly understood. Greater clarification of the selective mechanisms is achieved by investigating how major evolutionary transitions reduce spatiotemporal and energetic constraints on transmitting heritable code to offspring. Evolution toward less constrained flows is integral to enduring flow architecture everywhere, in both engineered and natural flow systems. Beginning approximately 4 billion years ago, the most basic level for transmitting genetic material to offspring was initiated by protocell division. Evidence from ribosomes suggests that protocells transmitted comma-free or circular codes, preceding the evolution of standard genetic code. This rudimentary information flow within protocells is likely to have first emerged within the geo-energetic and geospatial constraints of hydrothermal vents. A broad-gauged hypothesis is that major evolutionary transitions overcame such constraints with tri-flow adaptations. The interconnected triple flows incorporated energy-converting, spatiotemporal, and code-based informational dynamics. Such tri-flow adaptations stacked sequence splicing code on top of protein-DNA recognition code in eukaryotes, prefiguring the transition to sexual reproduction. Sex overcame the spatiotemporal-energetic constraints of binary fission with further code stacking. Examples are tubulin code and transcription initiation code in vertebrates. In a later evolutionary transition, language reduced metabolic-spatiotemporal constraints on inheritance by stacking phonetic, phonological, and orthographic codes. In organisms that reproduce sexually, each major evolutionary transition is shown to be a tri-flow adaptation that adds new levels of code-based informational exchange. Evolving biological complexity is also shown to increase the nongenetic transmissibility of code.

Immigrant use of public assistance and mode of entry: Demographics versus dependence.

A view that gained momentum in the 1990s, and which is sustained by some policy analysts and labor economists today, is that dependence on public assistance is greater for immigrants than for natives. Accordingly, this study investigates nativity differentials in the use of nine assistance programs, focusing on immigrant arrival cohorts within three distinct mode-of-entry proxy categories. The logistic regression analysis uses data from the 2013 CPS March supplement. To permit more nuanced interpretation, control variables are introduced hierarchically in a three-stage analysis. One new finding is that each of the three major regional-origin groups within the 1980-1995 refugee cohort-with an average length of residence exceeding two decades-sustains greater use of either SSI or Medicaid than natives. The study concludes that nativity differences in the use of public assistance continue to rest on the socio-demographic composition of three distinct populations, determined by mode of entry into the U.S.