Getting to YES. Negotiating Agreement Without Giving In

The Green Revolution boosted crop yields in developing nations by introducing dwarf genotypes of wheat and rice capable of responding to fertilisation without lodging. We now need a second Green Revolution, to improve the yield of crops grown in infertile soils by farmers with little access to fertiliser, who represent the majority of third-world farmers. Just as the Green Revolution was based on crops responsive to high soil fertility, the second Green Revolution will be based on crops tolerant of low soil fertility. Substantial genetic variation in the productivity of crops in infertile soil has been known for over a century. In recent years we have developed a better understanding of the traits responsible for this variation. Root architecture is critically important by determining soil exploration and therefore nutrient acquisition. Architectural traits under genetic control include basal-root gravitropism, adventitious-root formation and lateral branching. Architectural traits that enhance topsoil foraging are important for acquisition of phosphorus from infertile soils. Genetic variation in the length and density of root hairs is important for the acquisition of immobile nutrients such as phosphorus and potassium. Genetic variation in root cortical aerenchyma formation and secondary development (‘root etiolation’) are important in reducing the metabolic costs of root growth and soil exploration. Genetic variation in rhizosphere modification through the efflux of protons, organic acids and enzymes is important for the mobilisation of nutrients such as phosphorus and transition metals, and the avoidance of aluminum toxicity. Manipulation of ion transporters may be useful for improving the acquisition of nitrate and for enhancing salt tolerance. With the noteworthy exceptions of rhizosphere modification and ion transporters, most of these traits are under complex genetic control. Genetic variation in these traits is associated with substantial yield gains in low-fertility soils, as illustrated by the case of phosphorus efficiency in bean and soybean. In breeding crops for low-fertility soils, selection for specific root traits through direct phenotypic evaluation or molecular markers is likely to be more productive than conventional field screening. Crop genotypes with greater yield in infertile soils will substantially improve the productivity and sustainability of low-input agroecosystems, and in high-input agroecosystems will reduce the environmental impacts of intensive fertilisation. Although the development of crops with reduced fertiliser requirements has been successful in the few cases it has been attempted, the global scientific effort devoted to this enterprise is small, especially considering the magnitude of the humanitarian, environmental and economic benefits being forgone. Population growth, ongoing soil degradation and increasing costs of chemical fertiliser will make the second Green Revolution a priority for plant biology in the 21st century.

Roots of the Second Green Revolution

The study of phenotypic plasticity has progressed significantly over the past few decades. We have moved from variation for plasticity being considered as a nuisance in evolutionary studies to it being the primary target of investigations that use an array of methods, including quantitative and molecular genetics, as well as of several approaches that model the evolution of plastic responses. Here, I consider some of the major aspects of research on phenotypic plasticity, assessing where progress has been made and where additional effort is required. I suggest that some areas of research, such the study of the quantitative genetic underpinning of plasticity, have been either settled in broad outline or superseded by new approaches and questions. Other issues, such as the costs of plasticity are currently at the forefront of research in this field, and are likely to be areas of major future development.

/pdf/evolution-of-phenotypic-plasticity-where-are-we-going-now-56ahs2qo8d.pdf

Evolution of phenotypic plasticity: where are we going now?

ECOLOGY/EVOLUTION: Phenotypic Plasticity

Root system development is an important agronomic trait. The right architecture in a given environment allows plants to survive periods of water of nutrient deficit, and compete effectively for resources. Root systems also provide an optimal system for studying developmental plasticity, a characteristic feature of plant growth. This review proposes a framework for describing the pathways regulating the development of complex structures such as root systems: intrinsic pathways determine the characteristic architecture of the root system in a given plant species, and define the limits for plasticity in that species. Response pathways co-ordinate environmental cues with development by modulating intrinsic pathways. The current literature describing the regulation of root system development is summarized here within this framework. Regulatory pathways are also organized based on their specific developmental effect in the root system. All the pathways affect lateral root formation, but some specifically target initiation of the lateral root, while others target the development and activation of the lateral root primordium, or the elongation of the lateral root. Finally, we discuss emerging approaches for understanding the regulation of root system architecture.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-3040.2005.01306.x

Intrinsic and environmental response pathways that regulate root system architecture.

https://plantscience.psu.edu/research/labs/roots/publications/pdfs/Ho-JTB.pdf

Optimization modeling of plant root architecture for water and phosphorus acquisition

We examine if elections of public prosecutors (as is common in the U.S.) influence the way they handle cases. In particular, does it affect which cases are taken to trial? A theoretical model is constructed where voters use outcomes of the criminal justice system as a signal of prosecutor's quality. This leads to a distortion of the mix of cases they take to trial. Our results imply that when re-election pressures are high (i) prosecutors take too many cases to trial. This increases the number of convictions from trial and reduces the amount of plea bargaining so that (ii) the proportion of convictions stemming from trial increases. Consequently, (iii) the average sanction obtained in both jury trials and plea bargains decreases. A detailed dataset from North Carolina is used to identify empirical evidence of such distortions. Our empirical findings verify that elections do affect the decision of which cases to take to trial and confirms our three predictions.

The Effect of the Election of Prosecutors on Criminal Trials

A model Socrates' trial is presented. Two important features of the trial is, first, both the prosecutor and the defendant propose sanctions and, second, a jury takes a simple majority vote over the two proposals. This is shown to have good properties. First, a median-juror result is derived. This sanction is a Condorcet Winner among all possible sanctions. Second, the imposed sanction responds to both the harm of the act and the uncertainty of guilt. Third, under mild conditions, the expected sanction that arises should deter resulting in fewer crimes being committed.

The Trial of Socrates

Rock Paper Scissors is used to resolve conflict when a compromise is not possible. Individuals playing ``games'' tend to have biases they prefer to play. I show that Rock Paper Scissors with biased players results in a player with a high valuation for winning being victorious with a probability greater than a player with a low valuation. Thus, it frequently achieves the efficient outcome. Furthermore, as the benefit to victory increases for all players, victory for each player becomes equally likely. Therefore, it is often efficient for minor conflicts while it performs no better than a coin-flip for major conflicts.

Rock Paper Scissors

We examine whether elections of public prosecutors influence the mix of cases taken to trial versus plea bargained. A theoretical model is constructed wherein voters use outcomes of the criminal justice system as a signal of prosecutors’ quality, leading to a distortion in the mix of cases taken to trial. Using data from North Carolina we test whether reelection pressures lead to (a) an increase in the number and proportion of convictions from jury trials and (b) a decrease in the average sanction obtained in both jury trials and pleas. Our empirical findings are consistent with our theoretical predictions.

/pdf/the-effect-of-the-election-of-prosecutors-on-criminal-trials-3i9tkn7h8a.pdf

Bryan C. McCannon

Papers

Optimization modeling of plant root architecture for water and phosphorus acquisition

The Effect of the Election of Prosecutors on Criminal Trials

The Trial of Socrates

Rock Paper Scissors

The effect of the election of prosecutors on criminal trials