Feedback computability on Cantor space

We introduce the notion of feedback computable functions from $2^\omega$ to $2^\omega$, extending feedback Turing computation in analogy with the standard notion of computability for functions from $2^\omega$ to $2^\omega$. We then show that the feedback computable functions are precisely the effectively Borel functions. With this as motivation we define the notion of a feedback computable function on a structure, independent of any coding of the structure as a real. We show that this notion is absolute, and as an example characterize those functions that are computable from a Gandy ordinal with some finite subset distinguished

Folklore Term Paper: Folk Cures for the Common Cold

A handwritten term paper completed at Franklin and Marshall College by Robert Ackerman, dating from circa 1950. Within, Ackerman describes several interviews conducted across Berks, Lancaster, and Somerset counties relating to folk cures for the common cold.https://digitalcommons.ursinus.edu/shoemaker_documents/1282/thumbnail.jp

Reconciling Simulated and Observed Views of Clouds: MODIS, ISCCP, and the Limits of Instrument Simulators in Climate Models

The properties of clouds that may be observed by satellite instruments, such as optical depth and cloud top pressure, are only loosely related to the way clouds are represented in models of the atmosphere. One way to bridge this gap is through "instrument simulators," diagnostic tools that map the model representation to synthetic observations so that differences between simulator output and observations can be interpreted unambiguously as model error. But simulators may themselves be restricted by limited information available from the host model or by internal assumptions. This work examines the extent to which instrument simulators are able to capture essential differences between MODIS and ISCCP, two similar but independent estimates of cloud properties. We focus on the stark differences between MODIS and ISCCP observations of total cloudiness and the distribution of cloud optical thickness can be traced to different approaches to marginal pixels, which MODIS excludes and ISCCP treats as homogeneous. These pixels, which likely contain broken clouds, cover about 15% of the planet and contain almost all of the optically thinnest clouds observed by either instrument. Instrument simulators can not reproduce these differences because the host model does not consider unresolved spatial scales and so can not produce broken pixels. Nonetheless, MODIS and ISCCP observation are consistent for all but the optically-thinnest clouds, and models can be robustly evaluated using instrument simulators by excluding ambiguous observations

Canada at the Constitutional Crossroads

Canada has, of course, been at the constitutional crossroads for some time. As Dicey put it in 1885: \u27The preamble of the British North America Act, 1867, asserts with official mendacity that the Provinces of the present Dominion have expressed their desire to be united into one Dominion with a constitution similar in principle to that of the United Kingdom. If preambles were intended to express the truth, for the word Kingdom ought to have been substituted States. \u27 But Dicey was exaggerating. In dropping this line, he principally had in mind the Canadians\u27 adoption of a most un-British system of federal government, in which powers were divided between the dominion and its provinces

Summary of the VIN Field Program: Summer 1979

published or submitted for publicationis peer reviewedOpe

Perilesional edema in radiation necrosis reflects axonal degeneration

BACKGROUND: Recently, we characterized a Gamma Knife® radiation necrosis mouse model with various magnetic resonance imaging (MRI) protocols to identify biomarkers useful in differentiation from tumors. Though the irradiation was focal to one hemisphere, a contralateral injury was observed that appeared to be localized in the white matter only. Interestingly, this injury was identifiable in T2-weighted images, apparent diffusion coefficient (ADC), and magnetization transfer ratio (MTR) maps, but not on post-contrast T1-weighted images. This observation of edema independent of vascular changes is akin to the perilesional edema seen in clinical radiation necrosis. FINDINGS: The pathology underlying the observed white-matter MRI changes was explored by performing immunohistochemistry for healthy axons and myelin. The presence of both healthy axons and myelin was reduced in the contralateral white-matter lesion. CONCLUSIONS: Based on our immunohistochemical findings, the contralateral white-matter injury is most likely due to axonal degeneration