Epistemic Closure in Folk Epistemology

We report the results of four empirical studies designed to investigate the extent to which an epistemic closure principle for knowledge is reflected in folk epistemology. Previous work by Turri (2015a) suggested that our shared epistemic practices may only include a source-relative closure principle—one that applies to perceptual beliefs but not to inferential beliefs. We argue that the results of our studies provide reason for thinking that individuals are making a performance error when their knowledge attributions and denials conflict with the closure principle. When we used research materials that overcome what we think are difficulties with Turri’s original materials, we found that participants did not reject closure. Furthermore, when we presented Turri’s original materials to non-philosophers with expertise in deductive reasoning (viz., professional mathematicians), they endorsed closure for both perceptual and inferential beliefs. Our results suggest that an unrestricted closure principle—one that applies to all beliefs, regardless of their source—provides a better model of folk patterns of knowledge attribution than a source-relative closure principle

PHYSIOLOGICAL GENOMICS OF SPINAL CORD AND LIMB REGENERATION IN A SALAMANDER, THE MEXICAN AXOLOTL

Salamanders have a remarkable ability to regenerate complex body parts including the limb, tail, and central nervous system. Although salamander regeneration has been studied for several hundred years, molecular-level studies have been limited to a relatively few important transcription factors and signaling molecules that are highly conserved among animals. Physiological genomic approaches were used here to investigate spinal cord and limb regeneration. Chapter 2 reports that hundreds of gene expression changes were identified during spinal cord regeneration, showing that a diverse injury response is activated in concert with extracellular matrix remodeling mechanisms during the early acute phase of natural spinal cord regeneration. Chapter 3 presents results that identify the salamander ortholog of mammalian Nogo-A, a gene known to inhibit mammalian nerve axon regeneration. Nogo-A gene expression was characterized during salamander development and adulthood in order to address the roles of Nogo-A in the nervous system. Chapters 4 and 5 use physiological genomic approaches to examine limb regeneration and why this process is dependent upon an intact nerve supply. Results presented in Chapter 4 showed that many processes regulated during early limb regeneration do not depend upon nerve-derived factors, but striking differences arise between innervated and denervated limbs by 14 days after amputation. Chapter 5 identified genes associated with peripheral nerve axon regeneration and identified gene candidates that may be secreted by nerves to support limb regeneration. Lastly, chapter 6 characterizes the expression of a developmentally important family of genes, matrix metalloproteinases, during tail regeneration. These results suggest that matrix metalloproteinases play multiple roles throughout the regeneration process. Primarily, this dissertation presents data from the first genomic studies of salamander regeneration. The results suggest genes such as matrix metalloproteinases, and molecular pathways such as the Wnt and FGF signaling pathways that can be exploited to enhance regenerative ability in humans

Use of collaborative computer simulation activities by high school science students learning relative motion.

Galileo\u27s contemporaries as well as today\u27s students have difficulty understanding relative motion. It is hypothesized that construction of visual models, resolution of these visual models with numeric models, and, in many cases, rejection of epistemological commitments such as the belief in one true velocity, are necessary for students to form integrated mental models of relative motion events. To investigate students\u27 relative motion problem solving, high school science students were videotaped in classroom and laboratory settings as they performed collaborative predict-observe-explain activities with relative motion computer simulations. The activities were designed to facilitate conceptual change by challenging common alternative conceptions. Half of the students interacted with simulations that provided animated feedback; the other half received numeric feedback. Learning, as measured by a diagnostic test, occurred following both conditions. There was no statistically significant difference between groups on the measure. It is hypothesized that students did not show statistically significant performance differences on the relative motion test because (a) many students were able to solve numeric problems through algorithm use; (b) many numeric condition students were aided in their ability to visualize problems by interaction with the treatment; and (c) the animation condition fostered little learning because the activities were too easy for students to perform. Students\u27 problem solving was examined through analyses of protocols and through statistical analyses of written responses. Evidence supported the following findings: (1) Numeric condition students had more difficulty with the computer activities than animation condition students. (2) Many students in both groups were able to construct accurate mental models of relative motion events. (3) A number of numeric condition students used faulty mechanical algorithms to solve problems. (4) A number of animation condition students used visualization to solve problems, mapping dynamic visual features of the animations onto posttest problems. Thus, there is evidence that presentation of numeric data can foster students\u27 use of mechanical algorithms. Presentation of animations can foster visualization of target problems solved off-line. These results suggest that, in addition to the structure of the simulations, how computer simulations are used may have a great impact on students\u27 cognition

A Comparison of Two Commercial Swim Bench Ergometers in Determining Maximal Aerobic Power and Correlation to a Paddle Test in a Recreational Surfing Cohort

The recent addition of surfing to the Tokyo 2020 Olympic Games has fueled a surge in commercial and research interest in understanding the physiological demands of the sport. However, studies specific to maximal aerobic testing of surfers are scarce. Therefore, the primary aim of this study was to compare two commercially available swim bench (SWB) ergometers in the determination of maximal aerobic capacity in recreational surfers. A secondary aim was to correlate (independent of one another) the two ergometer findings of VO2peak to the time taken to complete a water-based 400-m paddle test. This cross-sectional study consisted of 17 recreational surfers aged between 18–58 years. Participants were randomized to either the SwimFast ergometer or VASA ergometer and tested for maximal aerobic capacity, followed by a 400-m paddle test. There were no significant differences between the two SWB ergometers in the determination of relative VO2peak (mean difference 0.33 mL/kg/min; 95% CI −1.24–1.90; p = 0.66). Correlations between VO2peak obtained from maximal paddling effort on the SwimFast and the VASA and the 400-m paddle test (total time (s)) showed a negative significant correlation r = −0.819, p = 0.024; r = −0.818, p = 0.024, respectively. Results suggest that either ergometer (SwimFast or VASA) can be used to determine peak aerobic capacity within a recreational surfing cohort. The significant correlation of the two SWB ergometers and the 400-m paddle test suggest that the 400-m paddle test may be a suitable field-based method of determining aerobic capability. Collectively, these preliminary findings provide initial evidence for similarities in VO2peak on two commercial ergometers and their correlations with a field-based test. However, further research is needed with a larger sample size and inclusive of competitive surfers to provide robust findings which can be generalized to the surfing population

Materials Democracy: An action plan for realising a redistributed materials economy

Human activities within the industrial economy are now the main and most significant drivers of change to the Earth System. These changes, driven by both the scale of human population and the magnifying effects of human technologies “are multiple, complex, interacting, often exponential in rate and globally significant in magnitude” (Steffen et al. 2004: 81). The years since the 1950s “have without doubt seen the most rapid transformation of the human relationship with the natural world in the history of humankind” (Steffen et al. 2004: 131). Over approximately the same period, the use of manufactured materials has increased by 4 to 15 times (Allwood et al. 2012: 7) and correlates with a rapid rise in global GDP. The expansion of the global economy is directly linked to the rise in land, sea and atmospheric pollution, natural habitat loss and the extraction and consumption of resources. Creating a future free of these destructive patterns will require the abandonment of the ‘take, make and throw away’ culture, moving toward a circular economy in which human wants and needs are met by managing resources at their highest utility for the longest time within biological and technical cycles. Without a wholesale recalibration of the global materials economy to factor in both immediate and long-term implications of all material decisions, inclusive of extraction to processing and transference to recapture, aspirations for a 21st-century circular economy will stall. This paper sets out a proposal for the development of an underlying common architecture and set of protocols for the generation, aggregation, and tracking of materials information in ways that are open, interoperable, and incorruptible. As such, materials information is envisioned as an open web of interconnected databases. The authors propose that such a materials information commons could empower stakeholders at all levels to make more effective decisions. For such an infrastructure to be operable and effective, a concerted and coordinated effort across all scales and sectors would need to be incentivised. This paper lays out the overarching context and need for such an undertaking and highlights both the opportunities and challenges therein. It surveys existing sources of materials information in order to expand upon and characterise recommended criteria for key material, technological, and behavioural functionalities. Lastly, this paper poses a number of areas of focus for future research

LMDA New and Noteworthy, March 2021

Contents include: Engagements beyond the numbers: Thoughts from a Dramaturg a year-ish into the pandemic; International Dramaturgy Lab Check In; LMDA Announces Grants and Awards Recipients; Renew Your Membership Today!; LMDA Conference 2021; Region Facebook Groups.https://soundideas.pugetsound.edu/lmdanewsletter/1057/thumbnail.jp

Thermal decomposition mechanisms of hafnium and zirconium silicates at the atomic scale

The hafnium and zirconium silicates, (MO2)(x)(SiO2)(1-x), with M=Hf/Zr, are being considered as high-k gate dielectrics for field-effect transistors as a compromise between high permittivity and thermal stability during processing. Using atomic-scale models of silicates derived from hafnon/zircon, stability before and after simulated thermal annealing is calculated within a density-functional approach. These silicates are found to be thermodynamically unstable with respect to decomposition into SiO2 and MO2 (M=Hf/Zr). Segregation mechanisms on the atomic scale are studied leading to an insight as to an why SiO2-rich mixtures undergo spinodal decomposition and why, by contrast, MO2-rich phases are metastable, decomposing below typical process temperatures

Macroinvertebrate diversity in fragmented Alpine streams: implications for freshwater conservation

Abstract.: Lakes and reservoirs disrupt the longitudinal connectivity of streams, considerably affecting benthic macroinvertebrate assemblages and diversity. Changes in assemblage composition within fragments can result from habitat alteration and reduced dispersal between fragments. We investigated the effects of habitat fragmentation in 10 Alpine streams, examining 69 taxa of benthic macroinvertebrates from 22 sites in fragmented and freeflowing streams. Total taxon richness (α-diversity) ranged from 6 to 27 in individual sites, and total richness was not significantly affected by fragmentation. However, Ephemeroptera and Diptera (excluding Simuliidae) richness was significantly reduced in stream fragments. Beta-diversity indicated a high degree of taxon turnover among sites within streams, but was not significantly different between fragmented and unfragmented streams. Characterizing the biological, physiological, and ecological traits of Ephemeroptera showed that communities in reservoir-fragmented streams had a higher affinity for fine sediments, increased temperatures, and reduced current velocity. Taxon assemblages in fragments were not nested subsets of unfragmented site assemblages. Thus, species turnover and species replacement in fragments is common, suggesting that most taxa are able to freely disperse among fragments. We suggest that habitat alteration was the primary cause of changes in assemblage structure in these streams. Consequently, habitat-based conservation is likely to be successful in maintaining populations of all but the weakest disperser

SPH Simulations of Accretion Disks and Narrow Rings

We model a massless viscous disk using Smoothed Particle Hydrodynamics (SPH) and note that it evolves according to the Lynden-Bell \& Pringle theory (1974) until a non-axisymmetric instability develops at the inner edge of the disk. This instability may have the same origin as the instability of initially axisymmetric viscous disks discussed by Lyubarskij et al. (1994). To clarify the evolution we evolved single and double rings of particles. It is actually inconsistent with the SPH scheme to set up a single ring as an initial condition because SPH assumes a smoothed initial state. As would be expected from an SPH simulation, the ring rapidly breaks up into a band. We analyse the stability of the ring and show that the predictions are confirmed by the simulation.Comment: 11 pages, uuencoded compressed postscript with 2 figs, accepted PASA. Also available at http://www.maths.monash.edu.au/~maddison/me/papers.htm