2,188 research outputs found
ECUT: Energy Conversion and utilization Technologies program biocatalysis research activity. Generation of chemical intermediates by catalytic oxidative decarboxylation of dilute organic acids
A rhodium-based catalyst was prepared and preliminary experiments were completed where the catalyst appeared to decarboxylate dilute acids at concentrations of 1 to 10 vol%. Electron spin resonance spectroscoy was used to characterize the catalyst as a first step leading toward modeling and optimization of rhodium catalysts. Also, a hybrid chemical/biological process for the production of hydrocarbons has been assessed. These types of catalysts could greatly increase energy efficiency of this process
Neutrino flux predictions for known Galactic microquasars
It has been proposed recently that Galactic microquasars may be prodigious
emitters of TeV neutrinos that can be detected by upcoming km^2 neutrino
telescopes. In this paper we consider a sample of identified microquasars and
microquasar candiates, for which available data enables rough determination of
the jet parameters. By employing the parameters inferred from radio
observations of various jet ejection events, we determine the neutrino fluxes
that should have been produced during these events by photopion production in
the jet. Despite the large uncertainties in our analysis, we demonstrate that
in several of the sources considered, the neutrino flux at Earth, produced in
events similar to those observed, would exceed the detection threshold of a
km^2 neutrino detector. The class of microquasars may contain also sources with
bulk Lorentz factors larger than those characteristic of the sample considered
here, directed along our line of sight. Such sources, which may be very
difficult to resolve at radio wavelengths and hence may be difficult to
identify as microqusar candidates, may emit neutrinos with fluxes significantly
larger than typically obtained in the present analysis. These sources may
eventually be identified through their neutrino and gamma-ray emission.Comment: 17 pages. Submitted to Ap
Actualities on molecular pathogenesis and repairing processes of cerebral damage in perinatal hypoxic-ischemic encephalopathy
Hypoxic-ischemic encephalopathy (HIE) is the most important cause of cerebral damage and long-term neurological sequelae in the perinatal period both in term and preterm infant
Electrical characterization of the Magellan batteries after storage
Two 22 cell batteries designed by Martin Marietta were tested. The batteries were rated at 26.5 Amp-Hr. The battery design is characterized by the following: Gates Aerospace 42B030AB15, 11 pos/12 neg, Pellon 2536 separator, passivated pos/teflonated neg. The tests can be summarized as follows: (1) no noticeable capacity loss after storage period; and (2) batteries exhibited larger non-uniformity of cell voltages during constant current charge
Automatic parallelization with separation logic
Separation logic is a recent approach to the analysis of pointer programs in which resource separation is expressed with a logical connective in assertions that describe the state at any given point in the program. We extend this approach to express properties of memory separation between different points in the program, and present an algorithm for determining independences between program statements which can be used for parallelization
Memory usage verification using Hip/Sleek.
Embedded systems often come with constrained memory footprints. It is therefore essential to ensure that software running on such platforms fulfils memory usage specifications at compile-time, to prevent memory-related software failure after deployment. Previous proposals on memory usage verification are not satisfactory as they usually can only handle restricted subsets of programs, especially when shared mutable data structures are involved. In this paper, we propose a simple but novel solution. We instrument programs with explicit memory operations so that memory usage verification can be done along with the verification of other properties, using an automated verification system Hip/Sleek developed recently by Chin et al.[10,19]. The instrumentation can be done automatically and is proven sound with respect to an underlying semantics. One immediate benefit is that we do not need to develop from scratch a specific system for memory usage verification. Another benefit is that we can verify more programs, especially those involving shared mutable data structures, which previous systems failed to handle, as evidenced by our experimental results
Spatial Interpolants
We propose Splinter, a new technique for proving properties of
heap-manipulating programs that marries (1) a new separation logic-based
analysis for heap reasoning with (2) an interpolation-based technique for
refining heap-shape invariants with data invariants. Splinter is property
directed, precise, and produces counterexample traces when a property does not
hold. Using the novel notion of spatial interpolants modulo theories, Splinter
can infer complex invariants over general recursive predicates, e.g., of the
form all elements in a linked list are even or a binary tree is sorted.
Furthermore, we treat interpolation as a black box, which gives us the freedom
to encode data manipulation in any suitable theory for a given program (e.g.,
bit vectors, arrays, or linear arithmetic), so that our technique immediately
benefits from any future advances in SMT solving and interpolation.Comment: Short version published in ESOP 201
SyQUAL: a Platform for Qualitative Modelling and Simulation of Biological Systems
Qualitative modelling in systems biology is increasingly adopted as it allows predicting important properties of biological systems even when quantitative information of such systems are unknown. Even though different tools for qualitative modelling have been recently proposed, their lack of automatism and their unstructured simulation core limit their applicability to non-complex biological networks. This paper presents SyQUAL, a platform for qualitative modelling and simulation of biological systems. It consists of two main layers: a Web-based framework that allows users to (i) import models described in the standard Systems Biology Markup Language (SBML), (ii) easily define properties to observe, and (iii) run simulations by hiding the underlying layer, that is, a SystemC-based core simulator that allows simulating the systems through a discrete event-based model of computation at different levels of details. The paper shows how SyQUAL has been applied to identify the attractors and to analyse the system robustness/sensitivity under perturbations of the Colitis-associated Colon Cancer (CAC) network
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