739 research outputs found
Semi-Endogenous R&D Growth Model with Negative Population Growth
This paper investigates the rates of technological progress, total output growth, and per capita output growth when population growth is negative by using a semi-endogenous R&D growth model. The analysis shows that within finite time, the employment share of the final goods sector reaches unity, the employment share of the R&D sector reaches zero, and accordingly, the rate of technological progress leads to zero. In this case, the growth rate of per capita output asymptotically approaches a positive value
Genomic characterization between strains selected for death-feigning duration for avoiding attack of a beetle
Predator avoidance is an important behavior that affects the degree of adaptation of organisms. We compared the DNA variation of one of the predator-avoidance behaviors, the recently extensively studied "death-feigning behavior", between the long strain bred for feigning death for a long time and the short strain bred for feigning death for a short time. To clarify how the difference in DNA sequences between the long and short strains corresponds to the physiological characteristics of the death-feigning duration at the transcriptome level, we performed comprehensive and comparative analyses of gene variants in Tribolium castaneum strains using DNA-resequencing. The duration of death feigning involves many gene pathways, including caffeine metabolism, tyrosine metabolism, tryptophan metabolism, metabolism of xenobiotics by cytochrome P450, longevity regulating pathways, and circadian rhythm. Artificial selection based on the duration of death feigning results in the preservation of variants of genes in these pathways in the long strain. This study suggests that many metabolic pathways and related genes may be involved in the decision-making process of anti-predator animal behavior by forming a network in addition to the tyrosine metabolic system, including dopamine, revealed in previous studies
Phase transitions of a tethered surface model with a deficit angle term
Nambu-Goto model is investigated by using the canonical Monte Carlo
simulations on fixed connectivity surfaces of spherical topology. Three
distinct phases are found: crumpled, tubular, and smooth. The crumpled and the
tubular phases are smoothly connected, and the tubular and the smooth phases
are connected by a discontinuous transition. The surface in the tubular phase
forms an oblong and one-dimensional object similar to a one-dimensional linear
subspace in the Euclidean three-dimensional space R^3. This indicates that the
rotational symmetry inherent in the model is spontaneously broken in the
tubular phase, and it is restored in the smooth and the crumpled phases.Comment: 6 pages with 6 figure
Ion current density profile of laser ablation plasma transported in multicusp magnetic field
Laser ion sources are capable of supplying ion
beams with high current because a laser produced
plasma has initially high number density same as
that of solid. [1]..
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