An ecological model of human information processing is introduced which characterizes intuition as a state oracle providing information for particular types of situations for which attunements to constraints have been developed. The consequences of this model are examined showing among other things that: for a cognitive task with a fixed problem space difficulty can only be reduced by introducing metaphor, difficulty of translation is minimum for a situationally equivalent metaphor, a situationally equivalent metaphor preserves and reflects extrinsic information about the situation, any situation containing a subcategory isomorphic to a problem situation can be made into a metaphor by supplying instructions, these characteristics can be exploited by an algorithm which chooses a metaphor in such a way that attunements are substituted for problem constraints and instructions are used as an "error term".

Genetic analyses of two hedgehog signal transduction network genes, Patched-1 and Gli2, has demonstrated a critical role for hedgehog signaling in mediating epithelial-stromal tissue interactions during ductal development. Disruption of either gene leads to similar, yet distinct, defects in ductal morphogenesis. Defects are mainly ductal dysplasias that closely resemble some hyperplasias of the human breast. Phenotypic analyses have been coupled with in situ hybridization, transplantation and tissue recombination analyses to formulate a model for tissue compartment-specific control of mouse mammary gland development by hedgehog signaling. In addition, the similarities among hedgehog mutation-induced ductal dysplasias and human breast pathologies suggest a role for altered hedgehog signaling in the development of mammary cancer.

Both normal development and neoplastic progression involve cellular transitions from one physiological state to another. Whereas much is being discovered about signal transduction networks involved in regulating these transitions, little progress has been made in identifying the higher order genetic determinants that establish and maintain mammary cell identity and dictate cell type-specific responses to mammotropic signals. Homeobox genes are a large superfamily of genes whose members function in establishing and maintaining cell fate and cell identity throughout embryonic development. Recent genetic and expression analyses strongly suggest that homeobox genes may perform similar functions at specific developmental transition points in the mammary gland. These analyses also suggest that homeobox genes may play a contributory or causal role in breast cancer.

This music score was submitted for the Kaleidoscope 2020 Call for Scores, an open access collaboration with the UCLA Music Library.

Isomorphic problems are to cognition what optical illusions are to perception. By drawing attention to anomalies such as problems which are identical in form but vary widely in difficulty they highlight cognitive processes normally hid- den a m o n g the minutiae of our theories. Results are reported from an experiment in which sub- jects solved a three disk Tower of Hanoi problem and its Monster Globe change isomorph using direct manipulation tableaus or paper and pencil. Subjects using direct manipulation were found to solve the Monster Globe problem in half the time taken by paper and pencil subjects. A n explana- tion revolving around attunement to environmen- tal constraints is advanced to account for this difference.

Analogy, conceptual change and problem reformulation have been central components in the exploration of human problem solving. A Situation Theoretic approach is developed to model analogy and conceptual change. This model is then used to relate a problem's representation to the associated cognitive difficulty. In this Unified framework the cognitive difficulty of isomorphic problem situations is defined in terms of the task, objects and relations of the problem situation. These compo?nents are then decomposed based on an Ecological Information Processing user model. The decomposition turns a problem sit?uation the structure and dynamics of the problem; the rules or constraints which are applicable; and the necessary instruc?tions for user interaction. From this, the cognitive difficulty associated with a problem representation is shown to be largely determined by the "instructional" component.

Teamwork in Team Space Fortress, a real-time cooperative task, was studied by analyzing the performance of participantspaired with different partners. To defeat the fortress, a player taking the role of bait approaches within the fortress rangeof fire causing the fortress to lower its shield to fire, thereby becoming vulnerable to attack by a partner playing therole of shooter. A novel design exchanging partners within four person groups allowed the identification of adaptationsand isolation of individual contributions to team performance. Team performance was determined by factors at bothindividual and team levels. Using subjective similarity rankings collected on Amazon Mechanical Turk, we constructedhigh-dimensional embeddings of similarity between team trajectories. Results showed that team members who adaptedmost, led to improved team performance. In re-pairings of partners better individual performance did not necessarily leadto better team performance again supporting the need for adaptivity in human machine teaming.

Background

Trypanosoma cruzi, causative agent of Chagas disease in humans and dogs, is a vector-borne zoonotic protozoan parasite that can cause fatal cardiac disease. While recognized as the most economically important parasitic infection in Latin America, the incidence of Chagas disease in the United States of America (US) may be underreported and even increasing. The extensive genetic diversity of T. cruzi in Latin America is well-documented and likely influences disease progression, severity and treatment efficacy; however, little is known regarding T. cruzi strains endemic to the US. It is therefore important to expand our knowledge on US T. cruzi strains, to improve upon the recognition of and response to locally acquired infections.

Methodology/principle findings

We conducted a study of T. cruzi molecular diversity in California, augmenting sparse genetic data from southern California and for the first time investigating genetic sequences from northern California. The vector Triatoma protracta was collected from southern (Escondido and Los Angeles) and northern (Vallecito) California regions. Samples were initially screened via sensitive nuclear repetitive DNA and kinetoplast minicircle DNA PCR assays, yielding an overall prevalence of approximately 28% and 55% for southern and northern California regions, respectively. Positive samples were further processed to identify discrete typing units (DTUs), revealing both TcI and TcIV lineages in southern California, but only TcI in northern California. Phylogenetic analyses (targeting COII-ND1, TR and RB19 genes) were performed on a subset of positive samples to compare Californian T. cruzi samples to strains from other US regions and Latin America. Results indicated that within the TcI DTU, California sequences were similar to those from the southeastern US, as well as to several isolates from Latin America responsible for causing Chagas disease in humans.

Conclusions/significance

Triatoma protracta populations in California are frequently infected with T. cruzi. Our data extend the northern limits of the range of TcI and identify a novel genetic exchange event between TcI and TcIV. High similarity between sequences from California and specific Latin American strains indicates US strains may be equally capable of causing human disease. Additional genetic characterization of Californian and other US T. cruzi strains is recommended.