From Mirror to Mirage: The Idea of Logical Space in Kant, Wittgenstein, and van Fraassen

This dissertation investigates the origin, intellectual development and use of a semantic variant of the idea of logical space found implicitly in Kant and explicitly in early Wittgenstein and van Fraassen. It elucidates the idea of logical space as the idea of images or pictures representative of reality organized into a logico-mathematical structure circumscribing a form of all possible worlds. Its main claim is that application of these images or pictures to reality is through a certain conception of self. The first chapter presents a novel interpretation of Kant’s semantic theory of schemata in the Critique of Pure Reason, showing that a structure of the imagination induced by the transcendental self informs an implicit idea of logical space. The second chapter offers an intellectual history of the idea through developments in the organization of images introduced by Helmholtz and Hertz. The third chapter reveals early Wittgenstein’s idea of logical space to be his notion of the self, demonstrating how this serves to unify propositions of the Tractatus Logico-Philosophicus concerning solipsism, realism, ethics, aesthetics and mysticism with those pertaining to the picture theory of meaning. The fourth chapter provides a historical overview of the development of van Fraassen’s empiricism in relation to his adaptation of logical space, and evaluates his recent proposal in Scientific Representation: Paradoxes of Perspective that the problem of coordination in the semantic view of theories is dissolved through self-location in logical space. After identifying a number of problems this proposal creates for his empiricism, a brief suggestion is made about how van Fraassen might improve upon his conception of logical space, and how an empiricist view of scientific representation might be understood as a result

Written Feedback in the Basic Course: What Instructors Provide and What Students Deem Helpful

Although the issue of speech evaluation has been a mainstay in our discipline, an updated discussion of written feedback merits our attention. To revisit this topic, this two-part content analysis first reveals the type of written feedback instructors offer students in basic public speaking classes. Building on these findings, the second part focuses on student perceptions of the helpfulness of the written feedback. The findings are collectively discussed and their implications for written evaluations of students\u27 oral performances are considered. Any instructor who has labored over written critiques, wondering whether students actually read and/or use the comments can value from this discussion

Layer-Resolved Ultrafast XUV Measurement of Hole Transport in a Ni-TiO2-Si Photoanode

Metal-oxide-semiconductor junctions are central to most electronic and optoelectronic devices. Here, the element-specificity of broadband extreme ultraviolet (XUV) ultrafast pulses is used to measure the charge transport and recombination kinetics in each layer of a Ni-TiO2-Si junction. After photoexcitation of silicon, holes are inferred to transport from Si to Ni ballistically in ~100 fs, resulting in spectral shifts in the Ni M2,3 XUV edge that are characteristic of holes and the absence of holes initially in TiO2. Meanwhile, the electrons are observed to remain on Si. After picoseconds, the transient hole population on Ni is observed to back-diffuse through the TiO2, shifting the Ti spectrum to higher oxidation state, followed by electron-hole recombination at the Si-TiO2 interface and in the Si bulk. Electrical properties, such as the hole diffusion constant in TiO2 and the initial hole mobility in Si, are fit from these transient spectra and match well with values reported previously

Slowing of axonal regeneration is correlated with increased axonal viscosity during aging

<p>Abstract</p> <p>Background</p> <p>As we age, the speed of axonal regeneration declines. At the biophysical level, why this occurs is not well understood.</p> <p>Results</p> <p>To investigate we first measured the rate of axonal elongation of sensory neurons cultured from neonatal and adult rats. We found that neonatal axons grew 40% faster than adult axons (11.5 µm/hour vs. 8.2 µm/hour). To determine how the mechanical properties of axons change during maturation, we used force calibrated towing needles to measure the viscosity (stiffness) and strength of substrate adhesion of neonatal and adult sensory axons. We found no significant difference in the strength of adhesions, but did find that adult axons were 3 times intrinsically stiffer than neonatal axons.</p> <p>Conclusions</p> <p>Taken together, our results suggest decreasing axonal stiffness may be part of an effective strategy to accelerate the regeneration of axons in the adult peripheral nervous system.</p

Temporal trends in the cardiorespiratory fitness of 2,525,827 adults between 1967 and 2016

Objective To estimate international and national temporal trends in the cardiorespiratory ftness (CRF) of adults, and to examine relationships between trends in CRF and trends in health-related, socioeconomic, and environmental indicators. Methods Data were obtained from a systematic search of studies that explicitly reported temporal trends in the CRF of apparently healthy adults aged 18–59 years. Sample-weighted temporal trends were estimated using best-ftting regression models relating the year of testing to mean CRF. Post-stratifed population-weighted mean changes in percent and standardized CRF were estimated. Pearson’s correlations were used to describe associations between linear trends in CRF and linear trends in health-related, socioeconomic, and environmental indicators. Results 2,525,827 adults representing eight high- and upper-middle-income countries between 1967 and 2016 collectively showed a moderate decline of 7.7% (95% CI −8.4 to −7.0) or 1.6% per decade (95% CI −1.7 to −1.5). Internationally, CRF improved in the 1960s and 1970s, and progressively declined at an increasing rate thereafter. Declines were larger for men than for women, and for young adults (\u3c40 \u3eyears) than for middle-aged adults (≥40 years). All countries experienced declines in CRF with a very strong negative correlation between CRF trends and obesity trends. Conclusions There has been a meaningful decline in the CRF of adults since 1980, which has progressively increased in magnitude over time, suggestive of a corresponding decline in population health. Continuous national and international surveillance systems are needed in order to monitor health and ftness trends, especially among low- and middle-income countries for which data do not currently exist. PROSPERO registration number: CRD42013003678

Wondering about telecentres : can they contribute to sustainable development in Latin America?

Spanish version available in IDRC Digital Library: Telecentros en la mira : cómo pueden contribuir al desarrollo social

Telecentros en la mira : cómo pueden contribuir al desarrollo social?

Versión en inglés disponible en la Biblioteca Digital del IDRC: Wondering about telecentres : can they contribute to sustainable development in Latin America?Publicado también en CHASQUI 66, junio, 1999 bajo el título: Telecentros y desarrollo socia

Enchanted by telecentres : a critical look at universal access to information technologies for international development; paper presented at the conference New IT and Inequality, University of Maryland, Feb. 16-17, 1999

Other version of: Wondering about telecentres : can they contribute to sustainable development in Latin Americ

Astrophysical Neutrino Event Rates and Sensitivity for Neutrino Telescopes

Spectacular processes in astrophysical sites produce high-energy cosmic rays which are further accelerated by Fermi-shocks into a power-law spectrum. These, in passing through radiation fields and matter, produce neutrinos. Neutrino telescopes are designed with large detection volumes to observe such astrophysical sources. A large volume is necessary because the fluxes and cross-sections are small. We estimate various telescopes' sensitivities and expected event rates from astrophysical sources of high-energy neutrinos. We find that an ideal detector of km^2 incident area can be sensitive to a flux of neutrinos integrated over energy from 10^5 and 10^{7} GeV as low as 1.3 * 10^(-8) * E^(-2) (GeV/cm^2 s sr) which is three times smaller than the Waxman-Bachall conservative upper limit on potential neutrino flux. A real detector will have degraded performance. Detection from known point sources is possible but unlikely unless there is prior knowledge of the source location and neutrino arrival time.Comment: Section added +modification