Toward the Construction of an Efficient Set of Robot Arm Operator Performance Metrics

As part of a larger project to identify and validate relevant quantitative measures of robot arm operator proficiency, fifteen metrics of arm maneuvering and hand controller performance were defined and measured for 3-DOF translational movement tasks. Twelve freshly trained operators provided performance data for seven target-acquisition task scenarios involving a variety of distance combinations along the X, Y, and Z axes. Metrics included indicators of task component times, distance traveled, inefficient (inverse) motion, maximum velocities, amount of multi-axis control, and input control onset times along the three axes. Pairwise correlations of all measures and scatter plots of variables yielding strong intercorrelations were examined to determine the potential underlying causes of the significant relationships. By identifying subsets of metrics with explainable co-dependencies, the overall metric set can be reduced to a limited number of key metrics that serve as effective discriminators of operator performance.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

Multiple Translocation of the AVR-Pita Effector Gene among Chromosomes of the Rice Blast Fungus Magnaporthe oryzae and Related Species

Magnaporthe oryzae is the causal agent of rice blast disease, a devastating problem worldwide. This fungus has caused breakdown of resistance conferred by newly developed commercial cultivars. To address how the rice blast fungus adapts itself to new resistance genes so quickly, we examined chromosomal locations of AVR-Pita, a subtelomeric gene family corresponding to the Pita resistance gene, in various isolates of M. oryzae (including wheat and millet pathogens) and its related species. We found that AVR-Pita (AVR-Pita1 and AVR-Pita2) is highly variable in its genome location, occurring in chromosomes 1, 3, 4, 5, 6, 7, and supernumerary chromosomes, particularly in rice-infecting isolates. When expressed in M. oryzae, most of the AVR-Pita homologs could elicit Pita-mediated resistance, even those from non-rice isolates. AVR-Pita was flanked by a retrotransposon, which presumably contributed to its multiple translocation across the genome. On the other hand, family member AVR-Pita3, which lacks avirulence activity, was stably located on chromosome 7 in a vast majority of isolates. These results suggest that the diversification in genome location of AVR-Pita in the rice isolates is a consequence of recognition by Pita in rice. We propose a model that the multiple translocation of AVR-Pita may be associated with its frequent loss and recovery mediated by its transfer among individuals in asexual populations. This model implies that the high mobility of AVR-Pita is a key mechanism accounting for the rapid adaptation toward Pita. Dynamic adaptation of some fungal plant pathogens may be achieved by deletion and recovery of avirulence genes using a population as a unit of adaptation

Hematopoiesis and leukemogenesis in mice expressing oncogenic NrasG12D from the endogenous locus

NRAS is frequently mutated in hematologic malignancies. We generated Mx1-Cre, Lox-STOP-Lox (LSL)-NrasG12D mice to comprehensively analyze the phenotypic, cellular, and biochemical consequences of endogenous oncogenic Nras expression in hematopoietic cells. Here we show that Mx1-Cre, LSL-NrasG12D mice develop an indolent myeloproliferative disorder but ultimately die of a diverse spectrum of hematologic cancers. Expressing mutant Nras in hematopoietic tissues alters the distribution of hematopoietic stem and progenitor cell populations, and Nras mutant progenitors show distinct responses to cytokine growth factors. Injecting Mx1-Cre, LSL-NrasG12D mice with the MOL4070LTR retrovirus causes acute myeloid leukemia that faithfully recapitulates many aspects of human NRAS-associated leukemias, including cooperation with deregulated Evi1 expression. The disease phenotype in Mx1-Cre, LSL-NrasG12D mice is attenuated compared with Mx1-Cre, LSL-KrasG12D mice, which die of aggressive myeloproliferative disorder by 4 months of age. We found that endogenous KrasG12D expression results in markedly elevated Ras protein expression and Ras-GTP levels in Mac1+ cells, whereas Mx1-Cre, LSL-NrasG12D mice show much lower Ras protein and Ras-GTP levels. Together, these studies establish a robust and tractable system for interrogating the differential properties of oncogenic Ras proteins in primary cells, for identifying candidate cooperating genes, and for testing novel therapeutic strategies