Mereological nihilism and the problem of emergence

Mereological nihilism is the view that there are no composite objects; everything in existence is mereologically simple. The view is subject to a number of difficulties, one of which concerns what I call the problem of emergence. Very briefly, the problem is that nihilism seems to be incompatible with emergent properties; it seems to rule out their very possibility. This is a problem because there are good independent reasons to believe that emergent properties are possible. This paper provides a solution to the problem. I will show that nihilism and emergence are perfectly compatible, providing one accepts a novel understanding of how objects can instantiate properties: what I call irreducibly collective instantiation

Probability for Decisions in Ancient Greece

8 pages, 1 article*Probability for Decisions in Ancient Greece* (Hall, David B.) 8 page

Mixing Designs: A General Model, Simplifications, and Some Minimal Designs

61 pages, 1 article*Mixing Designs: A General Model, Simplifications, and Some Minimal Designs* (Hall, David Benjamin) 61 page

New Approaches to the Analysis of Population Trends in Land Birds

54 pages, 1 article*New Approaches to the Analysis of Population Trends in Land Birds* (James, Frances C.; McCulloch, Charles E.; Wiedenfeld, David A.) 54 page

Annotated SAS Output (ASO)

92 pages, 1 article*Annotated SAS Output (ASO)* (Meredith, Michael P.; Lansky, David M.; Cady, Foster B.) 92 page

Improving the EM Algorithm

5 pages, 1 article*Improving the EM Algorithm* (Lansky, David; Casella, George) 5 page

Chronic Wasting Disease: The Effects of Environmental Prion Density and Interactions Between Populations on Disease Dynamics

27 pages, 1 article*Chronic Wasting Disease: The Effects of Environmental Prion Density and Interactions Between Populations on Disease Dynamics* (Hurtado, Paul; Mejran, Marcin; Morales, Thela; Schwager, David; Lanham, Michael) 27 page

Lateral Load Testing of the Advanced Stirling Convertor (ASC-E2) Heater Head

Free-piston Stirling convertors are fundamental to the development of NASA s next generation of radioisotope power system, the Advanced Stirling Radioisotope Generator (ASRG). The ASRG will use General Purpose Heat Source (GPHS) modules as the energy source and Advanced Stirling Convertors (ASCs) to convert heat into electrical energy, and is being developed by Lockheed Martin under contract to the Department of Energy. Achieving flight status mandates that the ASCs satisfy design as well as flight requirements to ensure reliable operation during launch. To meet these launch requirements, GRC performed a series of quasi-static mechanical tests simulating the pressure, thermal, and external loading conditions that will be experienced by an ASC E2 heater head assembly. These mechanical tests were collectively referred to as lateral load tests since a primary external load lateral to the heater head longitudinal axis was applied in combination with the other loading conditions. The heater head was subjected to the operational pressure, axial mounting force, thermal conditions, and axial and lateral launch vehicle acceleration loadings. To permit reliable prediction of the heater head s structural performance, GRC completed Finite Element Analysis (FEA) computer modeling for the stress, strain, and deformation that will result during launch. The heater head lateral load test directly supported evaluation of the analysis and validation of the design to meet launch requirements. This paper provides an overview of each element within the test and presents assessment of the modeling as well as experimental results of this task

Indicators of replicative damage in equine tendon fibroblast monolayers

<p>Background: Superficial digital flexor tendon (SDFT) injuries of horses usually follow cumulative matrix microdamage; it is not known why the reparative abilities of tendon fibroblasts are overwhelmed or subverted. Relevant in vitro studies of this process require fibroblasts not already responding to stresses caused by the cell culture protocols. We investigated indicators of replicative damage in SDFT fibroblast monolayers, effects of this on their reparative ability, and measures that can be taken to reduce it.</p> <p>Results: We found significant evidence of replicative stress, initially observing consistently large numbers of binucleate (BN) cells. A more variable but prominent feature was the presence of numerous gammaH2AX (γH2AX) puncta in nuclei, this being a histone protein that is phosphorylated in response to DNA double-stranded breaks (DSBs). Enrichment for injury detection and cell cycle arrest factors (p53 (ser15) and p21) occurred most frequently in BN cells; however, their numbers did not correlate with DNA damage levels and it is likely that the two processes have different causative mechanisms. Such remarkable levels of injury and binucleation are usually associated with irradiation, or treatment with cytoskeletal-disrupting agents.</p> <p>Both DSBs and BN cells were greatest in subconfluent (replicating) monolayers. The DNA-damaged cells co-expressed the replication markers TPX2/repp86 and centromere protein F. Once damaged in the early stages of culture establishment, fibroblasts continued to express DNA breaks with each replicative cycle. However, significant levels of cell death were not measured, suggesting that DNA repair was occurring. Comet assays showed that DNA repair was delayed in proportion to levels of genotoxic stress.</p> <p>Conclusions: Researchers using tendon fibroblast monolayers should assess their “health” using γH2AX labelling. Continued use of early passage cultures expressing initially high levels of γH2AX puncta should be avoided for mechanistic studies and ex-vivo therapeutic applications, as this will not be resolved with further replicative cycling. Low density cell culture should be avoided as it enriches for both DNA damage and mitotic defects (polyploidy). As monolayers differing only slightly in baseline DNA damage levels showed markedly variable responses to a further injury, studies of effects of various stressors on tendon cells must be very carefully controlled.</p&gt