322 research outputs found
Verifying procedural programs via constrained rewriting induction
This paper aims to develop a verification method for procedural programs via a transformation into Logically Constrained Term Rewriting Systems (LCTRSs). To this end, we extend transformation methods based on integer TRSs to handle arbitrary data types, global variables, function calls and arrays, as well as encode safety checks. Then we adapt existing rewriting induction methods to LCTRSs and propose a simple yet effective method to generalize equations. We show that we can automatically verify memory safety and prove correctness of realistic functions. Our approach proves equivalence between two implementations, so in contrast to other works, we do not require an explicit specification in a separate specification language
The association of positive psychological factors with work ability one year after myocardial infarction
Background Positive psychological factors like optimism, resilience and self-efficacy may facilitate successful adjustment after hospitalization for myocardial infarction (MI) and treatment with percutaneous coronary intervention (PCI), including return to work. Objective To examine whether positive psychological factors (optimism, resilience, and self-efficacy) predict work ability one year after PCI for MI. Methods Patients treated with PCI and with paid employment were included and completed questionnaires at 1 and 12âŻmonths post PCI discharge. Patients filled out the LOT-R optimism scale, the dispositional resilience scale (DRS-15), and the Cardiac Self-efficacy Scale (CSE) at 1-month, and the work ability index (WAI) at 1-year follow-up. Hierarchical linear regression models were used. Sensitivity analysis was performed for the acuteness of the PCI treatment. Results In total, 323 patients (14% women; mean age 59.5âŻÂ±âŻ6.8y; 74% acute PCI) completed both surveys. At 1-year follow-up, resilience (ÎČâŻ=âŻ0.152, pâŻ=âŻ0.009) and cardiac self-efficacy (ÎČâŻ=âŻ0.273, pâŻ<âŻ0.001), but not optimism (ÎČâŻ=âŻ0.044, pâŻ=âŻ0.432), were associated with work ability at 1âŻyear, irrespective of cardiac history, or sex. Age (ÎČâŻ=âŻâ0.158, pâŻ=âŻ0.002) and comorbidity index (ÎČâŻ=âŻâ0.104, pâŻ=âŻ0.044) were significant covariates. Sensitivity analysis revealed that in patients receiving an elective Conclusion Resilience and cardiac self-efficacy were independently associated with work ability 1âŻyear post PCI, whereas optimism was not. Identification and support of patients low in cardiac self-efficacy and resilience may contribute to improved restoration of work ability post PCI
CD97 neutralisation increases resistance to collagen-induced arthritis in mice
Synovial tissue of rheumatoid arthritis (RA) patients is characterised by an influx and retention of CD97-positive inflammatory cells. The ligands of CD97, CD55, chondroitin sulfate B, and α5ÎČ1 (very late antigen [VLA]-5) are expressed abundantly in the synovial tissue predominantly on fibroblast-like synoviocytes, endothelium, and extracellular matrix. Based upon this expression pattern, we hypothesise CD97 expression to result in accumulation of inflammatory cells in the synovial tissue of RA patients. To determine the therapeutic effect of blocking CD97 in an animal model of RA, collagen-induced arthritis was induced in a total of 124 DBA/J1 mice. Treatment was started on day 21 (early disease) or on day 35 (longstanding disease) with the blocking hamster anti-mouse CD97 monoclonal antibody (mAb) 1B2, control hamster immunoglobulin, or NaCl, applied intraperitoneally three times a week. The paws were evaluated for clinical signs of arthritis and, in addition, examined by radiological and histological analysis. Mice receiving 0.5 mg CD97 mAb starting from day 21 had significantly less arthritis activity and hind paw swelling. Furthermore, joint damage and inflammation were reduced and granulocyte infiltration was decreased. When treatment was started on day 35, CD97 mAb treatment had similar effects, albeit less pronounced. The results support the notion that CD97 contributes to synovial inflammation and joint destruction in arthritis
Diffusion of particles moving with constant speed
The propagation of light in a scattering medium is described as the motion of
a special kind of a Brownian particle on which the fluctuating forces act only
perpendicular to its velocity. This enforces strictly and dynamically the
constraint of constant speed of the photon in the medium. A Fokker-Planck
equation is derived for the probability distribution in the phase space
assuming the transverse fluctuating force to be a white noise. Analytic
expressions for the moments of the displacement along with an
approximate expression for the marginal probability distribution function
are obtained. Exact numerical solutions for the phase space
probability distribution for various geometries are presented. The results show
that the velocity distribution randomizes in a time of about eight times the
mean free time () only after which the diffusion approximation becomes
valid. This factor of eight is a well known experimental fact. A persistence
exponent of is calculated for this process in two dimensions
by studying the survival probability of the particle in a semi-infinite medium.
The case of a stochastic amplifying medium is also discussed.Comment: 9 pages, 9 figures(Submitted to Phys. Rev. E
Researching the use of force: The background to the international project
This article provides the background to an international project on use of force by the police that was carried out in eight countries. Force is often considered to be the defining characteristic of policing and much research has been conducted on the determinants, prevalence and control of the use of force, particularly in the United States. However, little work has looked at police officersâ own views on the use of force, in particular the way in which they justify it. Using a hypothetical encounter developed for this project, researchers in each country conducted focus groups with police officers in which they were encouraged to talk about the use of force. The results show interesting similarities and differences across countries and demonstrate the value of using this kind of research focus and methodology
Angular redistribution of near-infrared emission from quantum dots in 3D photonic crystals
We study the angle-resolved spontaneous emission of near-infrared light
sources in 3D photonic crystals over a wavelength range from 1200 to 1550 nm.
To this end PbSe quantum dots are used as light sources inside titania inverse
opal photonic crystals. Strong deviations from the Lambertian emission profile
are observed. An attenuation of 60 % is observed in the angle dependent radiant
flux emitted from the samples due to photonic stop bands. At angles that
correspond to the edges of the stop band the emitted flux is increased by up to
34 %. This increase is explained by the redistribution of Bragg-diffracted
light over the available escape angles. The results are quantitatively
explained by an expanded escape-function model. This model is based on
diffusion theory and adapted to photonic crystals using band structure
calculations. Our results are the first angular redistributions and escape
functions measured at near-infrared, including telecom, wavelengths. In
addition, this is the first time for this model to be applied to describe
emission from samples that are optically thick for the excitation light and
relatively thin for the photoluminesence light.Comment: 24 pages, 8 figures (current format = single column, double spaced
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