75 research outputs found
A Church Built on Charity: Augustine\u27s Ecclesiology
This thesis will undertake the mission of articulating the ecclesiological thought of Augustine with particular emphasis on charity as the fundamental component to church unity. Hopefully, this will further demonstrate his inclusivity, not exclusivity. The beginnings of this thesis will simply show his influences, and thus serve as a background to understanding the mind of Augustine. The next step will take the reader into the world of Augustine’s theology of charity. Charity in the Christian life is the result of being gifted with God’s grace; how charity works and how proper, authentic charity appears will be the topic of the section. The second section of this thesis will concern itself with Donatism and Augustine’s ecclesiology. It will examine multiple complementary views of Church held by Augustine: mystical communion, Body of Christ, field hospital, etc., and demonstrate where charity exists and why its existence is crucial for church unity. The final chapter will explore Augustine’s mature theology of nature and grace, in order to reflect his universal sense of a need for grace that sets everyone on the same level
First-Class Nonstandard Interpretations by Opening Closures
We motivate and discuss a novel functional programming construct
that allows convenient modular run-time nonstandard interpretation
via reflection on closure environments. This map-closure construct
encompasses both the ability to examine the contents of a
closure environment and to construct a new closure with a modified
environment. From the user’s perspective, map-closure is a
powerful and useful construct that supports such tasks as tracing,
security logging, sandboxing, error checking, profiling, code instrumentation
and metering, run-time code patching, and resource
monitoring. From the implementor’s perspective, map-closure
is analogous to call/cc. Just as call/cc is a non-referentiallytransparent
mechanism that reifies the continuations that are only
implicit in programs written in direct style, map-closure is a nonreferentially-
transparent mechanism that reifies the closure environments
that are only implicit in higher-order programs. Just as
CPS conversion is a non-local but purely syntactic transformation
that can eliminate references to call/cc, closure conversion
is a non-local but purely syntactic transformation that can eliminate
references to map-closure. We show how the combination
of map-closure and call/cc can be used to implement set! as
a procedure definition and a local macro transformation
Existential witness extraction in classical realizability and via a negative translation
We show how to extract existential witnesses from classical proofs using
Krivine's classical realizability---where classical proofs are interpreted as
lambda-terms with the call/cc control operator. We first recall the basic
framework of classical realizability (in classical second-order arithmetic) and
show how to extend it with primitive numerals for faster computations. Then we
show how to perform witness extraction in this framework, by discussing several
techniques depending on the shape of the existential formula. In particular, we
show that in the Sigma01-case, Krivine's witness extraction method reduces to
Friedman's through a well-suited negative translation to intuitionistic
second-order arithmetic. Finally we discuss the advantages of using call/cc
rather than a negative translation, especially from the point of view of an
implementation.Comment: 52 pages. Accepted in Logical Methods for Computer Science (LMCS),
201
Continuation-Passing C: compiling threads to events through continuations
In this paper, we introduce Continuation Passing C (CPC), a programming
language for concurrent systems in which native and cooperative threads are
unified and presented to the programmer as a single abstraction. The CPC
compiler uses a compilation technique, based on the CPS transform, that yields
efficient code and an extremely lightweight representation for contexts. We
provide a proof of the correctness of our compilation scheme. We show in
particular that lambda-lifting, a common compilation technique for functional
languages, is also correct in an imperative language like C, under some
conditions enforced by the CPC compiler. The current CPC compiler is mature
enough to write substantial programs such as Hekate, a highly concurrent
BitTorrent seeder. Our benchmark results show that CPC is as efficient, while
using significantly less space, as the most efficient thread libraries
available.Comment: Higher-Order and Symbolic Computation (2012). arXiv admin note:
substantial text overlap with arXiv:1202.324
Femoral Articular Cartilage Quality, but Not Thickness, Is Decreased for Anterior Cruciate Ligament Reconstruction Patients Relative to Control
Anterior cruciate ligament reconstruction (ACLR) patients are at risk of developing posttraumatic knee osteoarthritis (OA). The etiology of posttraumatic knee OA is complex, potentially involving biomechanical and biochemical factors. Changes in femoral cartilage thickness and composition are associated with knee OA, while current research is ambiguous on cartilage in ACLR patients. PURPOSE: This study aimed to compare femoral cartilage thickness and T2 relaxation time (a compositional measure) between ACLR patients and healthy controls in a resting state. We hypothesized that ACLR patients would exhibit thinner femoral cartilage and increased T2 relaxation times. METHODS: Twenty ACLR patients (6-24 months post-surgery) and 20 matched healthy controls were recruited following institutional board approval. Ultrasound and magnetic resonance imaging data were collected on two separate days, allowing cartilage thickness and composition measurements to be made, respectively. Statistical analyses, including independent t-tests and Holm-Bonferroni corrections, were performed on selected regions of interest. RESULTS: The ACLR group showed increased T2 relaxation times in four of eight femoral regions compared to controls. No significant differences in femoral cartilage thickness were observed between the groups. The primary finding from this study is that ACLR patients did not show differences in femoral cartilage thickness (a morphological measure), but displayed prolonged T2 relaxation times (a compositional measure) compared to controls, at rest. This finding suggests that compositional changes precede morphological shifts in femoral cartilage in early post-ACLR periods (6-24 months). CONCLUSION: These early compositional changes may indicate articular cartilage that is more compressible and subject to increased strain on the solid components of the joint. While ultrasound is a more accessible imaging method, magnetic resonance imaging may provide a more accurate and early evaluation of cartilage quality. Further research is needed to develop practical tools for early detection and monitoring of cartilage degradation in ACLR patients before progression into knee osteoarthritis
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Photoreversible interconversion of a phytochrome photosensory module in the crystalline state.
A major barrier to defining the structural intermediates that arise during the reversible photointerconversion of phytochromes between their biologically inactive and active states has been the lack of crystals that faithfully undergo this transition within the crystal lattice. Here, we describe a crystalline form of the cyclic GMP phosphodiesterases/adenylyl cyclase/FhlA (GAF) domain from the cyanobacteriochrome PixJ in Thermosynechococcus elongatus assembled with phycocyanobilin that permits reversible photoconversion between the blue light-absorbing Pb and green light-absorbing Pg states, as well as thermal reversion of Pg back to Pb. The X-ray crystallographic structure of Pb matches previous models, including autocatalytic conversion of phycocyanobilin to phycoviolobilin upon binding and its tandem thioether linkage to the GAF domain. Cryocrystallography at 150 K, which compared diffraction data from a single crystal as Pb or after irradiation with blue light, detected photoconversion product(s) based on Fobs - Fobs difference maps that were consistent with rotation of the bonds connecting pyrrole rings C and D. Further spectroscopic analyses showed that phycoviolobilin is susceptible to X-ray radiation damage, especially as Pg, during single-crystal X-ray diffraction analyses, which could complicate fine mapping of the various intermediate states. Fortunately, we found that PixJ crystals are amenable to serial femtosecond crystallography (SFX) analyses using X-ray free-electron lasers (XFELs). As proof of principle, we solved by room temperature SFX the GAF domain structure of Pb to 1.55-Ă… resolution, which was strongly congruent with synchrotron-based models. Analysis of these crystals by SFX should now enable structural characterization of the early events that drive phytochrome photoconversion
Drop on demand sample delivery for studying biocatalysts in action at X ray free electron lasers
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