The relation between derivations and syntactical structures in phrase-structure grammars

Conditions for a phrase-structure grammar (Chomsky 0-type grammar) are established which warrant that any of its derivations univocally defines a syntactical structure of the sentence. The simplifications for the particular cases of context-sensitive and context-free grammars are indicated

Three-dimensional myocardial strain estimation from volumetric ultrasound: experimental validation in an animal model

Although real-time three-dimensional echocardiography has the potential to allow for more accurate assessment of global and regional ventricular dynamics compared to the more traditional two-dimensional ultrasound examinations, it still requires rigorous testing and validation against other accepted techniques should it breakthrough as a standard examination in routine clinical practice. Very few studies have looked at a validation of regional functional indices in an in-vivo context. The aim of the present study therefore was to validate a previously proposed 3D strain estimation-method based on elastic registration of subsequent volumes on a segmental level in an animal model. Volumetric images were acquired with a GE Vivid7 ultrasound system in five open-chest sheep instrumented with ultrasonic microcrystals. Radial (epsilon(RR)), longitudinal (epsilon(LL)) and circumferential strain (epsilon(CC)) were estimated during four stages: at rest, during esmolol and dobutamine infusion, and during acute ischemia. Moderate correlations for epsilon(LL) (r=0.63; p<0.01) and epsilon(CC) (r=0.60; p=0.01) were obtained, whereas no significant radial correlation was found. These findings are comparable to the performance of the current state-of-the-art commercial 3D speckle tracking methods

Health status deterioration in subjects with mild to moderate airflow obstruction, a six years observational study

BackgroundPatients with COPD need to cope with a disabling disease, which leads to health status impairment.AimTo investigate the long term change of health status in subjects with mild to moderate airflow obstruction and to compare this to subjects without airflow obstruction, with and without a smoking history. Second, to investigate the factors potentially associated to rapid health status decline in our total cohort.MethodsTwo hundred and one subjects were included. Generic [Short form 36 health survey (SF36) and EuroQol - 5 dimensions (EQ-5D)] and disease specific [Clinical COPD questionnaire (CCQ) and COPD Assessment Test (CAT)] health status questionnaires were regularly repeated over a six years period. Other functional outcomes comprised measures of lung function, physical fitness, physical activity and emotional state.ResultsOn average, health status decline did not differ between groups with the exception of the EQ-5D index, which deteriorated faster in subjects with airflow obstruction compared to the never smoking control group [-0.018(0.008) versus 0.00006(0.003), p=0.03]. Subjects presenting at least one exacerbation had faster rate of deterioration measured with CAT [0.91(0.21) versus -0.26(0.25), p<0.01]. Characteristics of the fast declining group were older age, worse lung function, physical fitness, physical activity and disease specific baseline health status. Subjects with airflow obstruction had a 2.5 (95% CI 1.36-4.71) higher risk of presenting fast overall health status decline. Fast overall decline was associated with the presence of acute exacerbation(s) (44% of the subjects with exacerbation(s) versus 17% of subjects without exacerbation, p=0.03). Changes in fat free mass, functional exercise capacity and in symptoms of anxiety and depression correlated weakly to changes in health status measured with all questionnaires.ConclusionSubjects with mild airflow obstruction present a significant deterioration of health status, which is generally not much faster compared to smoking and never smoking controls. Subjects with fast decline in overall health status are older and more likely to have airflow obstruction, acute respiratory exacerbation(s), reduced physical fitness, physical activity and impaired COPD specific health status at baseline.Trial registrationNCT01314807 - retrospectively registered on March 2011

LEX : a case study in development and validation of formal specifications

The paper describes an experiment in the combined use of various tools for the development and validation of formal specifications. The first tool consists of a very abstract, (non-executable) axiomatic specification language. The second tool consists of an (executable) constructive specification language. Finally, the third tool is a verification system. The first two tools were used to develop two specifications for the same case study, viz. a generic scanner similar to the tool LEX present in UNIX. Reflecting the nature of the tools the first specification is abstract and non-executable, whereas the second specification is less abstract but executable. Thereupon the verification system was used to formally prove that the second specification is consistent with the first in that it describes the same problem. During this proof it appeared that both specifications contained conceptual errors (adequacy errors). It is argued that the combined use of tools similar to those employed in the experiment may substantially increase the quality of the software developed