524 research outputs found
How the hydrogen bond in NHF is revealed with Compton scattering
In order to probe electron wave functions involved in the bonding of NHF,
we have performed Compton scattering experiments in an oriented single crystal
and in a powder. Ab initio calculations of the Compton profiles for NHF and
NHCl are used to enlighten the nature of the bonds in the NHF crystal.
As a consequence, we are able to show significant charge transfer in the
ammonium ion which is not observable using other methods. Our study provides a
compelling proof for hydrogen bond formation in NHF.Comment: 4 pages, 5 figures, accepted for publication as a Regular Article in
Physical Review
Laboratory and on-road tests assessment of fine and ultrafine particle emission factors for EURO6 LPG passenger cars
Correlates of Depressive and Anxiety Symptoms in Young Adults with Spina Bifida *
Objective Based on social ecological theory, this study was designed to examine the unique relationships between multi-level ecological factors and psychological symptoms in young adults with spina bifida (SB). Method A sample of 61 individuals with SB, 18–25 years of age, completed standardized self-report measures of attitude toward SB, satisfaction with family functioning, Chronic Care Model (CCM) services, and depressive and anxiety symptoms. A chart review yielded SB clinical data. Results High rates of depressive and anxiety symptoms were found. Hierarchical regression analysis identified the proximal individual (attitude toward SB) and family (satisfaction with family functioning) factors as more strongly related to depressive symptoms than the distal healthcare system factor (CCM services). Self-reported pain was the only ecological factor associated with anxiety symptoms. Conclusions Study findings provide a potential foundation for multi-factor screening of young adults with SB at risk for psychological symptoms
Reducing the environmental impacts of passenger cars: a comparison between electricity and biofuels
Oxygen disorder in ice probed by X-ray Compton scattering
We use electron momentum density in ice as a tool to quantify order-disorder
transitions by comparing Compton profiles differences of ice VI, VII, VIII and
XII with respect to ice Ih. Quantitative agreement is found between theory and
experiment for ice VIII, which is the most ordered phase. Robust signatures of
the oxygen disorder are identified in the momentum density for the VIII-VII ice
phase transition. The unique aspect of this work is the determination of the
fraction n_e of electron directly involved in phase transitions as well as the
use of position space signatures for quantifying oxygen site disorder.Comment: 3 figures, 2 tables. Accepted for publication in Phys. Rev.
Untyping Typed Algebras and Colouring Cyclic Linear Logic
We prove "untyping" theorems: in some typed theories (semirings, Kleene
algebras, residuated lattices, involutive residuated lattices), typed equations
can be derived from the underlying untyped equations. As a consequence, the
corresponding untyped decision procedures can be extended for free to the typed
settings. Some of these theorems are obtained via a detour through fragments of
cyclic linear logic, and give rise to a substantial optimisation of standard
proof search algorithms.Comment: 21
Sessions as Propositions
Recently, Wadler presented a continuation-passing translation from a
session-typed functional language, GV, to a process calculus based on classical
linear logic, CP. However, this translation is one-way: CP is more expressive
than GV. We propose an extension of GV, called HGV, and give translations
showing that it is as expressive as CP. The new translations shed light both on
the original translation from GV to CP, and on the limitations in
expressiveness of GV.Comment: In Proceedings PLACES 2014, arXiv:1406.331
Observed communication semantics for classical processes
Classical Linear Logic (CLL) has long inspired readings of its proofs as communicating processes. Wadler's CP calculus is one of these readings. Wadler gave CP an operational semantics by selecting a subset of the cut-elimination rules of CLL to use as reduction rules. This semantics has an appealing close connection to the logic, but does not resolve the status of the other cut-elimination rules, and does not admit an obvious notion of observational equivalence. We propose a new operational semantics for CP based on the idea of observing communication, and use this semantics to define an intuitively reasonable notion of observational equivalence. To reason about observational equivalence, we use the standard relational denotational semantics of CLL. We show that this denotational semantics is adequate for our operational semantics. This allows us to deduce that, for instance, all the cut-elimination rules of CLL are observational equivalences
Islet Oxygen Consumption Rate (OCR) Dose Predicts Insulin Independence in Clinical Islet Autotransplantation
Background: Reliable in vitro islet quality assessment assays that can be performed routinely, prospectively, and are able to predict clinical transplant outcomes are needed. In this paper we present data on the utility of an assay based on cellular oxygen consumption rate (OCR) in predicting clinical islet autotransplant (IAT) insulin independence (II). IAT is an attractive model for evaluating characterization assays regarding their utility in predicting II due to an absence of confounding factors such as immune rejection and immunosuppressant toxicity. Methods: Membrane integrity staining (FDA/PI), OCR normalized to DNA (OCR/DNA), islet equivalent (IE) and OCR (viable IE) normalized to recipient body weight (IE dose and OCR dose), and OCR/DNA normalized to islet size index (ISI) were used to characterize autoislet preparations (n = 35). Correlation between pre-IAT islet product characteristics and II was determined using receiver operating characteristic analysis. Results: Preparations that resulted in II had significantly higher OCR dose and IE dose (p<0.001). These islet characterization methods were highly correlated with II at 6–12 months post-IAT (area-under-the-curve (AUC) = 0.94 for IE dose and 0.96 for OCR dose). FDA/PI (AUC = 0.49) and OCR/DNA (AUC = 0.58) did not correlate with II. OCR/DNA/ISI may have some utility in predicting outcome (AUC = 0.72). Conclusions: Commonly used assays to determine whether a clinical islet preparation is of high quality prior to transplantation are greatly lacking in sensitivity and specificity. While IE dose is highly predictive, it does not take into account islet cell quality. OCR dose, which takes into consideration both islet cell quality and quantity, may enable a more accurate and prospective evaluation of clinical islet preparations
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