The dynamics of Machiavellian intelligence

The "Machiavellian intelligence" hypothesis (or the "social brain" hypothesis) posits that large brains and distinctive cognitive abilities of humans have evolved via intense social competition in which social competitors developed increasingly sophisticated "Machiavellian" strategies as a means to achieve higher social and reproductive success. Here we build a mathematical model aiming to explore this hypothesis. In the model, genes control brains which invent and learn strategies (memes) which are used by males to gain advantage in competition for mates. We show that the dynamics of intelligence has three distinct phases. During the dormant phase only newly invented memes are present in the population. During the cognitive explosion phase the population's meme count and the learning ability, cerebral capacity (controlling the number of different memes that the brain can learn and use), and Machiavellian fitness of individuals increase in a runaway fashion. During the saturation phase natural selection resulting from the costs of having large brains checks further increases in cognitive abilities. Overall, our results suggest that the mechanisms underlying the "Machiavellian intelligence" hypothesis can indeed result in the evolution of significant cognitive abilities on the time scale of 10 to 20 thousand generations. We show that cerebral capacity evolves faster and to a larger degree than learning ability. Our model suggests that there may be a tendency toward a reduction in cognitive abilities (driven by the costs of having a large brain) as the reproductive advantage of having a large brain decreases and the exposure to memes increases in modern societies.Comment: A revised version has been published by PNA

High grade lymphoma in the nasopharynx presented as sudden onset of bilateral blindness

BACKGROUND: Sudden onset of bilateral blindness is rare; hysteria, cortical infarction or bilateral central retinal arterial occlusion can cause this. CASE PRESENTATION: The authors describe a single case of sudden onset bilateral blindness in a patient with nasopharyngeal carcinoma, which is unusual. Biopsy revealed a high-grade lymphoma. After treatment the patient made a complete visual recovery, with no evidence of visual sequelae and no clear reasons for this complete recovery. CONCLUSION: CT and MR imaging did not demonstrate any lesions invading any part of the visual pathway or even indeed the occipital cortex. High dose steroids may have reduced the mass effect of the tumour or the blindness may have been hysterical but is unlikely

An analysis of the XOR dynamic problem generator based on the dynamical system

This is the post-print version of the article - Copyright @ 2010 Springer-VerlagIn this paper, we use the exact model (or dynamical system approach) to describe the standard evolutionary algorithm (EA) as a discrete dynamical system for dynamic optimization problems (DOPs). Based on this dynamical system model, we analyse the properties of the XOR DOP Generator, which has been widely used by researchers to create DOPs from any binary encoded problem. DOPs generated by this generator are described as DOPs with permutation, where the fitness vector is changed according to a permutation matrix. Some properties of DOPs with permutation are analyzed, which allows explaining some behaviors observed in experimental results. The analysis of the properties of problems created by the XOR DOP Generator is important to understand the results obtained in experiments with this generator and to analyze the similarity of such problems to real world DOPs.This work was supported by Brazil FAPESP under Grant 04/04289-6 and by UK EPSRC under Grant EP/E060722/2

McMullin On-Farm Flood Capture and Recharge Project: Hydrologic and Hydraulic Analyses (H&H), final report

Approval of a Hydrologic and Hydraulic Analyses (H&H) by California Department of Water Resources (DWR) is a pre-requisite for projects being funded through DWR’s Flood Corridor Program. The H&H needs to show early in the project schedule in analysis acceptable to DWR that the project will produce the anticipated flood risk reduction benefits. A Benefit:Cost (B/C) ratio provides a metric for comparing benefits from a project in relation to DWR costs for the project. In our analysis, we calculated a B/C of 1.86 for Phase 1, the diversion of 150 cubic feet per second (cfs) from the Kings River onto the project during flood flow conditions between December and May, and of 1.98 for Phase 2/3, the diversion of 500 cfs from the Kings River onto the project during the same conditions. We provide background on the project and the area that will be affected by the project (the study area), summarize our methods, and present our findings. Two large hydrologic issues face the Kings Basin: severe and chronic overdraft of about 0.16M ac-ft annually, and flood risks along the Kings River and the downstream San Joaquin River. Since 1983, downstream communities along the Kings and San Joaquin Rivers have suffered over $1B in flood damages (2013$). To help mitigate these two issues, this project proposes diverting and capturing Kings River floodwater at the James Bypass onto agricultural lands adjacent to the Kings River for conjunctive use purposes (e.g. recharge, in lieu recharge, irrigation). This project is planned in three phases: Phase 1 (Ph1) will divert 150 cubic feet per second (cfs) onto agricultural fields from December through May and 100 cfs from June through September. Fifty-five hundred acres are planned for enrollment in Ph1 with 375 acres under flood easements; 1,125 acres managed under dual purpose of accepting flood flows and being managed for farming; and the remaining acreage receiving flood flows when available for in lieu recharge. Phases 2 and 3 (Ph 2/3) together will expand enrollment to 16,000 acres with expected equivalent ratios for flood easements, dual purpose and farming. Ph2/3 is planned to have a 500 cfs flood diversion and capture capacity. We assessed hydrologic and hydraulics conditions and economics for these planned phases following the scope of work defined in Task Order 1 between Kings River Conservation District (KRCD) and Tetra Tech

Integrative analysis of clinicopathological features defines novel prognostic models for mantle cell lymphoma in the immunochemotherapy era: A report from The North American Mantle Cell Lymphoma Consortium

BACKGROUND: Patients with mantle cell lymphoma (MCL) exhibit a wide variation in clinical presentation and outcome. However, the commonly used prognostic models are outdated and inadequate to address the needs of the current multidisciplinary management of this disease. This study aims to investigate the clinical and pathological features of MCL in the immunochemotherapy era and improve the prognostic models for a more accurate prediction of patient outcomes. METHODS: The North American Mantle Cell Lymphoma Project is a multi-institutional collaboration of 23 institutions across North America to evaluate and refine prognosticators for front-line therapy. A total of 586 MCL cases diagnosed between 2000 and 2012 are included in this study. A comprehensive retrospective analysis was performed on the clinicopathological features, treatment approaches, and outcomes of these cases. The establishment of novel prognostic models was based on in-depth examination of baseline parameters, and subsequent validation in an independent cohort of MCL cases. RESULTS: In front-line strategies, the use of hematopoietic stem cell transplantation was the most significant parameter affecting outcomes, for both overall survival (OS, p \u3c 0.0001) and progression-free survival (PFS, p \u3c 0.0001). P53 positive expression was the most significant pathological parameter correlating with inferior outcomes (p \u3c 0.0001 for OS and p = 0.0021 for PFS). Based on the baseline risk factor profile, we developed a set of prognostic models incorporating clinical, laboratory, and pathological parameters that are specifically tailored for various applications. These models, when tested in the validation cohort, exhibited strong predictive power for survival and showed a stratification resembling the training cohort. CONCLUSIONS: The outcome of patients with MCL has markedly improved over the past two decades, and further enhancement is anticipated with the evolution of clinical management. The innovative prognostic models developed in this study would serve as a valuable tool to guide the selection of more suitable treatment strategies for patients with MCL

Predicting polarization enhancement in multicomponent ferroelectric superlattices

Ab initio calculations are utilized as an input to develop a simple model of polarization in epitaxial short-period CaTiO3/SrTiO3/BaTiO3 superlattices grown on a SrTiO3 substrate. The model is then combined with a genetic algorithm technique to optimize the arrangement of individual CaTiO3, SrTiO3 and BaTiO3 layers in a superlattice, predicting structures with the highest possible polarization and a low in-plane lattice constant mismatch with the substrate. This modelling procedure can be applied to a wide range of layered perovskite-oxide nanostructures providing guidance for experimental development of nanoelectromechanical devices with substantially improved polar properties.Comment: 4 pages, submitted to PR

Effects of Drought on Forests and Rangelands in the United States: A Comprehensive Science Synthesis

This assessment provides input to the reauthorized National Integrated Drought Information System (NIDIS) and the National Climate Assessment (NCA), and it establishes the scientific foundation needed to manage for drought resilience and adaptation. Focal areas include drought characterization; drought impacts on forest processes and disturbances such as insect outbreaks and wildfire; and consequences on forest and rangeland values. Drought can be a severe natural disaster with substantial social and economic consequences. Drought becomes most obvious when large-scale changes are observed; however, even moderate drought can have long-lasting impacts on the structure and function of forests and rangelands without these obvious large-scale changes. Large stand-level impacts of drought are already underway in the West, but all U.S. forests are vulnerable to drought. Drought-associated forest disturbances are expected to increase with climatic change. Management actions can either mitigate or exacerbate the effects of drought. A first principal for increasing resilience and adaptation is to avoid management actions that exacerbate the effects of current or future drought. Options to mitigate drought include altering structural or functional components of vegetation, minimizing drought-mediated disturbance such as wildfire or insect outbreaks, and managing for reliable flow of water

Genetic algorithm dynamics on a rugged landscape

The genetic algorithm is an optimization procedure motivated by biological evolution and is successfully applied to optimization problems in different areas. A statistical mechanics model for its dynamics is proposed based on the parent-child fitness correlation of the genetic operators, making it applicable to general fitness landscapes. It is compared to a recent model based on a maximum entropy ansatz. Finally it is applied to modeling the dynamics of a genetic algorithm on the rugged fitness landscape of the NK model.Comment: 10 pages RevTeX, 4 figures PostScrip