5,241 research outputs found
Standing on Shaky Ground: Americans' Experiences With Economic Insecurity
Based on 2009 Surveys of Economic Risk Perceptions and Insecurity, examines Americans' experience of economic insecurity, such as frequency and duration, buffers against hardship, and concerns by income, family structure, race/ethnicity, and education
Elastic suspension of a wind tunnel test section
Experimental verification of the theory describing arbitrary motions of an airfoil is reported. The experimental apparatus is described. A mechanism was designed to provide two separate degrees of freedom without friction or backlash to mask the small but important aerodynamic effects of interest
A distinct development programme for the cranial paraxial mesoderm
Cells of the cranial paraxial mesoderm give rise to parts of the skull and muscles of the head. Some mesoderm cells migrate from locations close to the hindbrain into the branchial arches where they undergo muscle differentiation. We have characterised these migratory pathways in chick embryos either by DiI-labelling cells before migration or by grafting quail cranial paraxial mesoderm orthotopically. These experiments demonstrate that depending on their initial rostrocaudal position, cranial paraxial mesoderm cells migrate to fill the core of specific branchial arches. A survey of the expression of myogenic genes showed that the myogenic markers Myf5, MyoD and myogenin were expressed in branchial arch muscle, but at comparatively late stages compared with their expression in the somites. Pax3 was not expressed by myogenic cells that migrate into the branchial arches despite its expression in migrating precursors of limb muscles. In order to test whether segmental plate or somitic mesoderm has the ability to migrate in a cranial location, we grafted quail trunk mesoderm into the cranial paraxial mesoderm region. While segmental plate mesoderm cells did not migrate into the branchial arches, somitic cells were capable of migrating and were incorporated into the branchial arch muscle mass. Grafted somitic cells in the vicinity of the neural tube maintained expression of the somitic markers Pax3, MyoD and Pax1. By contrast, ectopic somitic cells located distal to the neural tube and in the branchial arches did not express Pax3. These data imply that signals in the vicinity of the hindbrain and branchial arches act on migrating myogenic cells to influence their gene expression and developmental pathways
Comparison of Methods for Determining the Composition of Pyrolysis Products from the Degradation of Ablative Composites. Status report.
Determining composition of pyrolysis products from degradation of ablative material
How Not to Think About Managed Care
The claim of this Article is that the concept of managed care, like many concepts now prominent in commentary about medical care finance and delivery in the United States, is incoherent and thus a barrier to useful analysis. To demonstrate this conclusion, we first discuss the managerial context in which managed care claims have arisen and outline the diverse trends to which the category is regularly and confusingly applied. We then suggest an alternative approach to characterizing recent changes in medical care and show how this approach alters and deepens our understanding of recent economic and political developments. We conclude by arguing for more neutral categories to make sense of past and projected developments in methods of reimbursement, techniques of management, and organizational structures
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