7 research outputs found

    ~ (H1’92 ABSTRACT GARDENERS AND GURUS: PATTERNS OF COOPERATION AMONG CAD USERS

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    We studied CAD system users to find out how they use the sophisticated customization and extension facilities offered by many CAD products. We found that users of varying levels of expertise collaborate to customize their CAD environments and to create programmatic extensions to their applications. Within a group of users, there is at Ieast one local expert who provides support for other users. We call this persona local developer. The local developer is a fellow domain expert, not a professionrd programmer, outside technical constdtant or MIS staff member. We found that in some CAD environments the support role has been formalized so that local developers are given official recognition, and time and resources to pursue Iocal developer activities. In general, this formalization of the locaI deveIoper role appears successful. We discuss the implications of our findings for work practices and for software design

    Recruitment of Novel Calcium-Binding Proteins for Root Nodule Symbiosis in Medicago truncatula

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    Legume rhizobia symbiotic nitrogen (N(2)) fixation plays a critical role in sustainable nitrogen management in agriculture and in the Earth's nitrogen cycle. Signaling between rhizobia and legumes initiates development of a unique plant organ, the root nodule, where bacteria undergo endocytosis and become surrounded by a plant membrane to form a symbiosome. Between this membrane and the encased bacteria exists a matrix-filled space (the symbiosome space) that is thought to contain a mixture of plant- and bacteria-derived proteins. Maintenance of the symbiosis state requires continuous communication between the plant and bacterial partners. Here, we show in the model legume Medicago truncatula that a novel family of six calmodulin-like proteins (CaMLs), expressed specifically in root nodules, are localized within the symbiosome space. All six nodule-specific CaML genes are clustered in the M. truncatula genome, along with two other nodule-specific genes, nodulin-22 and nodulin-25. Sequence comparisons and phylogenetic analysis suggest that an unequal recombination event occurred between nodulin-25 and a nearby calmodulin, which gave rise to the first CaML, and the gene family evolved by tandem duplication and divergence. The data provide striking evidence for the recruitment of a ubiquitous Ca(2+)-binding gene for symbiotic purposes

    Racial Disparities in COVID-19 Outcomes Among Black and White Patients With Cancer

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