Empirical Analysis of Mutation Operator Selection Strategies for Genetic Improvement

Genetic improvement (GI) tools find improved program versions by modifying the initial program. These can be used for the purpose of automated program repair (APR). GI uses software transformations, called mutation operators, such as deletions, insertions, and replacements of code fragments. Current edit selection strategies, however, under-explore the search spaces of insertion and replacement operators. Therefore, we implement a uniform strategy based on the relative operator search space sizes. We evaluate it on the QuixBugs repair benchmark and find that the uniform strategy has the potential for improving APR tool performance. We also analyse the efficacy of the different mutation operators with regard to the type of code fragment they are applied to. We find that, for all operators, choosing expression statements as target statements is the most successful for finding program variants with improved or preserved fitness (50.03%, 33.12% and 23.85% for deletions, insertions and replacements, respectively), whereas choosing declaration statements is the least effective (3.16%, 10.82% and 3.14% for deletions, insertions and replacements)

Phase Transition Study of Superconducting Microstructures

The presented results are part of a feasibility study of superheated superconducting microstructure detectors. The microstructures (dots) were fabricated using thin film patterning techniques with diameters ranging from $50\mu$m up to $500\mu$m and thickness of $1\mu$m. We used arrays and single dots to study the dynamics of the superheating and supercooling phase transitions in a magnetic field parallel to the dot surface. The phase transi- tions were produced by either varying the applied magnetic field strength at a constant temperature or changing the bath temperature at a constant field. Preliminary results on the dynamics of the phase transitions of arrays and single indium dots will be reported.Comment: 7pages in LaTex format, five figures available upon request by [email protected], preprint Bu-He 93/

Implementation of an evidence-based sepsis program in the intensive care unit: evident or not?

Severe sepsis and septic shock are among the most serious health conditions and are associated with unwelcome clinical, social, and economic outcomes. With the introduction of the Surviving Sepsis Campaign guidelines, the campaign leaders aimed to reduce mortality from severe sepsis by at least one quarter by 2009 by means of a six-point action plan, namely, building awareness among health care professionals, improving early and accurate disease recognition and diagnosis, increasing the use of appropriate treatments and interventions, education, getting better post-intensive care unit access, and developing standard processes of care. However, adherence to these recommendations is a first but crucial step in obtaining these goals. A comprehensive evaluation of both, adherence to a sepsis program and whether this results in better outcomes for patients, is therefore essential to guide informed decision-making regarding the implementation of such an evidence-based protocol

Visual intracortical and transthalamic pathways carry distinct information to cortical areas.

Sensory processing involves information flow between neocortical areas, assumed to rely on direct intracortical projections. However, cortical areas may also communicate indirectly via higher-order nuclei in the thalamus, such as the pulvinar or lateral posterior nucleus (LP) in the visual system of rodents. The fine-scale organization and function of these cortico-thalamo-cortical pathways remains unclear. We find that responses of mouse LP neurons projecting to higher visual areas likely derive from feedforward input from primary visual cortex (V1) combined with information from many cortical and subcortical areas, including superior colliculus. Signals from LP projections to different higher visual areas are tuned to specific features of visual stimuli and their locomotor context, distinct from the signals carried by direct intracortical projections from V1. Thus, visual transthalamic pathways are functionally specific to their cortical target, different from feedforward cortical pathways, and combine information from multiple brain regions, linking sensory signals with behavioral context

Macrofauna assemblages in a XVIIth century shipwreck: comparison with those on natural reefs and sandy bottoms

The macrofauna assemblages of a XVIIth century shipwreck off southern Portugal were studied and compared with those of nearby natural reefs and sandy bottoms, by underwater visual census. A total of 11 173 specimens of 224 different fauna taxa and 12 phyla were recorded. Natural reefs had the highest density of specimens (35 122 / 1000 m2) followed by the shipwreck (21 392 / 1000 m2) and the sandy bottoms (3771 / 1000 m2). Three biodiversity indices were estimated (Margalef, Shannon- Wiener and Pielou), with the natural reefs showing the highest values. However, the shipwreck presented values relatively similar to those of the natural reefs for the Shannon-Wiener and Pielou indices. The three habitats were clearly distinguishable by multivariate statistical analysis, with the average dissimilarity between sand and shipwreck, and between sand and natural reefs being much higher than that between the shipwreck and the natural reefs. The shipwreck had higher abundances of some commercially important species, such as the pouting Trisopterus luscus, European conger Conger conger, and common spider crab Maja squinado, as well as some vulnerable and threatened species such as the pink seafan Eunicella verrucosa. The results presented emphasize the importance of this habitat on the southern Portuguese coast.info:eu-repo/semantics/publishedVersio