On zeros of Martin-L\"of random Brownian motion

We investigate the sample path properties of Martin-L\"of random Brownian motion. We show (1) that many classical results which are known to hold almost surely hold for every Martin-L\"of random Brownian path, (2) that the effective dimension of zeroes of a Martin-L\"of random Brownian path must be at least 1/2, and conversely that every real with effective dimension greater than 1/2 must be a zero of some Martin-L\"of random Brownian path, and (3) we will demonstrate a new proof that the solution to the Dirichlet problem in the plane is computable

Skepticism about Reasoning

Less discussed than Hume’s skepticism about what grounds there could be for projecting empirical hypotheses is his concern with a skeptical regress that he thought threatened to extinguish any belief when we reflect that our reasoning is not perfect. The root of the problem is the fact that a reflection about our reasoning is itself a piece of reasoning. If each reflection is negative and undermining, does that not give us a diminution of our original belief to nothing? It requires much attention to detail, we argue, to determine whether or not there is a skeptical problem in this neighborhood. For consider, if we subsequently doubt a doubt we had about our reasoning, should that not restore some confidence in our original belief? We would then have instead an alternating sequence of pieces of skeptical reasoning that cancel each others’ effects on our justification in the original proposition, at least to some degree. We will argue that the outcome of the sequence of reflections Hume is imagining depends on information about a given case that is not known a priori. We conclude this from the fact that under three precise, explanatory, and viable contemporary reconstructions of what this kind of reasoning about reasoning could be like and how it has the potential to affect our original beliefs, a belief-extinguishing regress is not automatic or necessary. The outcome of the sequence of reflections depends on further information whose character we will explain

Guerrilla Open Access

In the 1990s, the Internet offered a horizon from which to imagine what society could become, promising autonomy and self-organization next to redistribution of wealth and collectivized means of production. While the former was in line with the dominant ideology of freedom, the latter ran contrary to the expanding enclosures in capitalist globalization. This antagonism has led to epochal copyrights, where free software and piracy kept the promise of radical commoning alive. Free software, as Christopher Kelty writes in this pamphlet, provided a model ‘of a shared, collective, process of making software, hardware and infrastructures that cannot be appropriated by others’. Well into the 2000s, it served as an inspiration for global free culture and open access movements who were speculating that distributed infrastructures of knowledge production could be built, as the Internet was, on top of free software. For a moment, the hybrid world of advanced Internet giants—sharing code, advocating open standards and interoperability—and users empowered by these services, convinced almost everyone that a new reading/writing culture was possible. Not long after the crash of 2008, these disruptors, now wary monopolists, began to ingest smaller disruptors and close off their platforms. There was still free software somewhere underneath, but without the ‘original sense of shared, collective, process’. So, as Kelty suggests, it was hard to imagine that for-profit academic publishers wouldn't try the same with open access

Expression of Ixodes scapularis Antifreeze Glycoprotein Enhances Cold Tolerance in Drosophila melanogaster

Drosophila melanogaster experience cold shock injury and die when exposed to low non-freezing temperatures. In this study, we generated transgenic D. melanogaster that express putative Ixodes scapularis antifreeze glycoprotein (IAFGP) and show that the presence of IAFGP increases the ability of flies to survive in the cold. Male and female adult iafgp-expressing D. melanogaster exhibited higher survival rates compared with controls when placed at non-freezing temperatures. Increased hatching rates were evident in embryos expressing IAFGP when exposed to the cold. The TUNEL assay showed that flight muscles from iafgp-expressing female adult flies exhibited less apoptotic damage upon exposure to non-freezing temperatures in comparison to control flies. Collectively, these data suggest that expression of iafgp increases cold tolerance in flies by preventing apoptosis. This study defines a molecular basis for the role of an antifreeze protein in cryoprotection of flies

Martin-Löf Randomness and Brownian Motion

We investigate the Martin-L�of random sample paths of Brownian motion, applying techniques from algorithmic randomness to Brownian motion, an active area of research in probability theory. In Chapter 2, we investigate many classical results about one dimensional Brownian motion in the context of Martin-L�of randomness. We show that many results which are known to hold almost surely for the Brownian motion process - including results concerning the modulus of continuity, points of increase, time inversion, and law of large numbers - hold for every Martin-L�of random sample path. We also show that scaling invariance and the strong Markov property hold for every Martin-L�of random path, with suitable effectivization. In Chapter 3, we investigate the zero set of one-dimensional Brownian motion. We prove that the set of zeroes is characterized by having high effective dimension. We also demonstrate that, although the zeroes are highly noncomputable in the sense of effective dimension, many of them are layerwise computable from a Brownian path. In Chapter 4, we give a new proof that the solution to the Dirichlet problem in the plane is computable. It is a well-known result of Kakutani that the solution to the Dirichlet problem can be found using expected hitting times of Brownian paths to the boundary. We show that the hitting times of Martin-L�of random Brownian paths on a computable boundary are layerwise computable in the path, and thus the expected value of the hitting times is computable, and so the solution to the Dirichlet problem is computable. In Chapter 5, we further investigate planar Martin-L�of random Brownian motion. We demonstrate that a Martin-L�of random planar Brownian path only hits points such that the path is not random relative to those points (except the origin), which implies that a Martin-L�of random planar path has area zero and that every point except the origin is hit by only measure 0 many paths. We also show that every Martin-L�of random planar Brownian path has points of uncountable multiplicity

Quantum dynamics of adsorbed H2 in the microporous framework MOF-5 analyzed using diffuse reflectance infrared spectroscopy

Diffuse reflectance infrared spectroscopy is used to measure the quantum dynamics of molecular hydrogen adsorbed in the microporous material MOF-5. Low-temperature spectra reveal at least three distinct binding sites. The induced redshifts in the vibrational mode frequencies allow the estimation of site-specific binding energies ranging from 2.5 to 4 kJ/mol. Splittings in the rovibrational sidebands are consistent with the existing theories and indicate that H2 is relatively freely rotating even at temperatures as low as 10 K. Ortho to para conversion of the adsorbed H2 is observed to occur over the course of several hours. A translational sideband of 84 cm-1 arises from the center-of-mass motion of H2 at the primary adsorption site and indicates that the zero-point energy is a substantial fraction of the binding energy of this site

Quantum dynamics of adsorbed H2 in the microporous framework MOF-5 analyzed using diffuse reflectance infrared spectroscopy

Diffuse reflectance infrared spectroscopy is used to measure the quantum dynamics of molecular hydrogen adsorbed in the microporous material MOF-5. Low-temperature spectra reveal at least three distinct binding sites. The induced redshifts in the vibrational mode frequencies allow the estimation of site-specific binding energies ranging from 2.5 to 4 kJ/mol. Splittings in the rovibrational sidebands are consistent with the existing theories and indicate that H2 is relatively freely rotating even at temperatures as low as 10 K. Ortho to para conversion of the adsorbed H2 is observed to occur over the course of several hours. A translational sideband of 84 cm-1 arises from the center-of-mass motion of H2 at the primary adsorption site and indicates that the zero-point energy is a substantial fraction of the binding energy of this site