ECONOMIC GROWTH AND EVOLUTION: PARENTAL PREFERENCE FOR QUALITY AND QUANTITY OF OFFSPRING

This paper presents a quantitative analysis of the model developed in Galor and Moav, Natural Selection and the Origin of Economic Growth (2002), in which agents vary genetically in their preference for quality and quantity of children. We simulate a parametric form of the model, enabling examination of the transition from Malthusian stagnation to modern rates of economic growth. The simulations allow an assessment of the strength of the biological foundations of the model and demonstrate the susceptibility of the modern high-growth state to invasion by cheaters. Extending the model from two to three genotypes suggests the possibility of a return to Malthusian conditions rather than a permanent state of modern growth.

Deception: neurological foundations, cognitive processes, and practical forensic applications

Deception is a foundational part of everyday interactions, and everyone will be deceived and will be a deceiver at some point in their life. When examining the brain while telling a lie, neuroimaging studies have shown an increased activity in the prefrontal cortex. While some evidence does not find a correlation between deception and prefrontal activity, different types of deception activating different brain regions could explain this. The prefrontal cortex is responsible for planning and executive control, which appears to be the main cognitive process associated with deception. This is evidenced by the ability to lie increasing as executive function develops in young children, and that lying becomes more difficult when executive function is strained. Lie detection in forensic settings is the most applicable use of the cognition of deception, and interviewers that use cognitive methods to detect deception do so at a significantly higher rate than chance (50%). Despite this finding, law enforcement and other investigative careers have not fully implemented cognitive deception detection into practice

When deception gets personal: an exploration into personality\u27s link to deception

Most of our understanding of deceptive behaviors comes from cognitive (Vrij, Fisher, & Blank, 2015) or social psychological (Ekman, 2009) perspectives, and furthermore comes from forensic deception detection research and strategies (Vrij, 2008). One psychological domain that has not had as much investigation in relation to deception is personality. The present study examines the connection between personality traits and one aspect of deceptive behaviors – motivations to lie. College students completed self-report surveys online regarding personality, their lying habits, and basic demographic questions. Additionally, participants read several lying scenarios and rated the likelihood of lying. In a sample of 292 participants, several connections were observed between lying motives and Big Five traits, facet level traits, and dark personality traits. In sum, there were significant and differentiating connections between motivations for lying and personality characteristics; however, it is best to focus on patterns of relationships due to the exploratory nature of the study

Compaction Testing of Granular Material

The South Dakota Department of Transportation SDDOT uses the Ohio Highway Department’s Typical Moisture Density Curves for preforming compaction quality control on granular soil materials in junction with standard moisture density relations. The SDDOT also uses the Nuclear Density Gauge NDG, Sand Cone, and Rubber Balloon methods to conduct in-situ density tests. Compaction quality control of recycled pavements is conducted using test strips. The test strip method works well for large areas but becomes problematic for small areas. The ODOT Materials Manual states “Moisture-Density proctor curves and controls were originally developed to be used on cohesive (clays and silts) soils. Errors or complications arise when trying to extrapolate these principals to granular materials” (ODOT, 1998). The SDDOT has also been using more materials recycled from PCC pavements and asphalt concrete pavements as subbase and base courses. For these reasons the SDDOT wishes to reevaluate its current methods compaction quality control of granular materials. A research synthesis report published by the National Cooperative Highway Research Program (NCHRP) has summarized alternative methods used by other DOTs for compaction quality control of granular materials (Nazzal, 2014). The research presented within this report includes the development of a new family of curves for SDDOT encountered base and subbase granular materials and also recommends Dynamic Cone Penetrometer (DCP) methods for compaction quality control of granular materials. The research conducted included a literature review of various alternative forms of granular compaction quality control and analysis of the adequacy of using families of moisture density curves for granular compaction of base and subbase granular materials encountered by the SDDOT. The results of the research indicated that the currently used Ohio Highway Department’s Typical Moisture Density Curves may be over predicting the maximum dry unit weight of base and subbase materials encountered by the SDDOT. The results of an alternatives analysis also indicated that the DCP device may be the best alternative in-situ compaction testing device to meet the needs of the SDDOT

Heat flow in InAs/InP heterostructure nanowires

The transfer of heat between electrons and phonons plays a key role for thermal management in future nanowire-based devices, but only a few experimental measurements of electron-phonon (e-ph) coupling in nanowires are available. Here, we combine experimental temperature measurements on an InAs/InP heterostructure nanowire system with finite element modeling (FEM) to extract information on heat flow mediated by e-ph coupling. We find that the electron and phonon temperatures in our system are highly coupled even at temperatures as low as 2 K. Additionally, we find evidence that the usual power-law temperature dependence of electron-phonon coupling may not correctly describe the coupling in nanowires and show that this result is consistent with previous research on similar one-dimensional electron systems. We also compare the strength of the observed e-ph coupling to a theoretical analysis of e-ph interaction in InAs nanowires, which predicts a significantly weaker coupling strength than observed experimentally.Comment: 9 pages, 6 figure

Competitiveness of Brazilian Sugarcane Ethanol Compared to US Corn Ethanol

Corn ethanol produced in the US and sugarcane ethanol produced in Brazil are the world’s leading sources of biofuel. Current US biofuel policies create both incentives and constraints for the import of ethanol from Brazil, and together with the competitiveness and greenhouse gas intensity of sugarcane ethanol compared to corn ethanol will determine the extent of these imports. This study analyzes the supply-side determinants of this competitiveness and compares the greenhouse gas intensity of corn ethanol and sugarcane ethanol delivered to US ports. We find that while the cost of sugarcane ethanol production in Brazil is lower than that of corn ethanol in the US, the inclusion of transportation costs for the former and co-product credits for the latter changes their relative competitiveness. We also find that the relative cost of ethanol in the US and Brazil is highly sensitive to the prevailing exchange rate and prices of feedstocks. At an exchange rate of US$1 = R$2.15 the cost of corn ethanol is 15% lower than the delivered cost of sugarcane ethanol at a US port. Sugarcane ethanol has lower GHG emissions than corn ethanol but a price of over $113 per ton of CO2 is needed to affect competitiveness.economic competitiveness, renewable fuel standard, ethanol trade policy, Agribusiness, Agricultural and Food Policy,

Deconvoluting mTOR biology

In metazoans, TOR is an essential protein that functions as a master regulator of cellular growth and proliferation. Over the past decade, there has been an explosion of information about this critical master kinase, ranging from the composition of the TOR protein complex to its ability to act as an integrator of numerous extracellular signals. Unfortunately, this plethora of information has also raised numerous questions regarding TOR function. Currently, the prevailing view is that mammalian TOR (mTOR) exists in at least two molecular complexes, mTORC1 and mTORC2, which are largely defined by the presence of either RAPTOR or RICTOR. However, additional co-factors have been identified for each complex, and their importance in mediating mTOR signals has been incompletely elucidated. Similarly, there are differences in mTOR function that reflect the tissue of origin. In this review, we present an alternative view to mTOR complex formation and function, which envisions mTOR regulation and signal propagation as a reflection of cell type- and basal state-dependent conditions. The re-interpretation of mTOR biology in this framework may facilitate the design of therapies most likely to effectively inhibit this central regulator of cell behavior

It\u27s getting complicated-A fresh look at p53-MDM2-ARF triangle in tumorigenesis and cancer therapy

Anti-tumorigenic mechanisms mediated by the tumor suppressor p53, upon oncogenic stresses, are our bodies\u27 greatest weapons to battle against cancer onset and development. Consequently, factors that possess significant p53-regulating activities have been subjects of serious interest from the cancer research community. Among them, MDM2 and ARF are considered the most influential p53 regulators due to their abilities to inhibit and activate p53 functions, respectively. MDM2 inhibits p53 by promoting ubiquitination and proteasome-mediated degradation of p53, while ARF activates p53 by physically interacting with MDM2 to block its access to p53. This conventional understanding of p53-MDM2-ARF functional triangle have guided the direction of p53 research, as well as the development of p53-based therapeutic strategies for the last 30 years. Our increasing knowledge of this triangle during this time, especially through identification of p53-independent functions of MDM2 and ARF, have uncovered many under-appreciated molecular mechanisms connecting these three proteins. Through recognizing both antagonizing and synergizing relationships among them, our consideration for harnessing these relationships to develop effective cancer therapies needs an update accordingly. In this review, we will re-visit the conventional wisdom regarding p53-MDM2-ARF tumor-regulating mechanisms, highlight impactful studies contributing to the modern look of their relationships, and summarize ongoing efforts to target this pathway for effective cancer treatments. A refreshed appreciation of p53-MDM2-ARF network can bring innovative approaches to develop new generations of genetically-informed and clinically-effective cancer therapies

Nondiffusive spin dynamics in a two-dimensional electron gas

We describe measurements of spin dynamics in the two-dimensional electron gas in GaAs=GaAlAs quantum wells. Optical techniques, including transient spin-grating spectroscopy, are used to probe the relaxation rates of spin polarization waves in the wave vector range from zero to 6 x 104 cm-1. We find that the spin polarization lifetime is maximal at a nonzero wave vector, in contrast with expectations based on ordinary spin diffusion, but in quantitative agreement with recent theories that treat diffusion in the presence of spin-orbit couplin