Image Utility Assessment and a Relationship with Image Quality Assessment

International audiencePresent quality assessment (QA) algorithms aim to generate scores for natural images consistent with subjective scores for the quality assessment task. For the quality assessment task, human observers evaluate a natural image based on its perceptual resemblance to a reference. Natural images communicate useful information to humans, and this paper investigates the utility assessment task, where human observers evaluate the usefulness of a natural image as a surrogate for a reference. Current QA algorithms implicitly assess utility insofar as an image that exhibits strong perceptual resemblance to a reference is also of high utility. However, a perceived quality score is not a proxy for a perceived utility score: a decrease in perceived quality may not affect the perceived utility. Two experiments are conducted to investigate the relationship between the quality assessment and utility assessment tasks. The results from these experiments provide evidence that any algorithm optimized to predict perceived quality scores cannot immediately predict perceived utility scores. Several QA algorithms are evaluated in terms of their ability to predict subjective scores for the quality and utility assessment tasks. Among the QA algorithms evaluated, the visual information fidelity (VIF) criterion, which is frequently reported to provide the highest correlation with perceived quality, predicted both perceived quality and utility scores reasonably. The consistent performance of VIF for both the tasks raised suspicions in light of the evidence from the psychophysical experiments. A thorough analysis of VIF revealed that it artificially emphasizes evaluations at finer image scales (i.e., higher spatial frequencies) over those at coarser image scales (i.e., lower spatial frequencies). A modified implementation of VIF, denoted VIF*, is presented that provides statistically significant improvement over VIF for the quality assessment task and statistically worse performance for the utility assessment task. A novel utility assessment algorithm, referred to as the natural image contour evaluation (NICE), is introduced that conducts a comparison of the contours of a test image to those of a reference image across multiple image scales to score the test image. NICE demonstrates a viable departure from traditional QA algorithms that incorporate energy-based approaches and is capable of predicting perceived utility scores

An AraC/XylS family transcriptional regulator homologue from Bacteroides fragilis is associated with cell survival following DNA damage

A putative transcriptional regulator of the AraC/XylS family was identified in a genomic genebank of Bacteroides fragilis Bf-1, which partially relieved the sensitivity of Escherichia coli DNA repair mutants to the DNA-damaging agents, metronidazole and mitomycin C. A homologue of this gene with the same phenotype was identified as BF638R3281 in B. fragilis 638R. Transcription of BF638R3281 was constitutive with respect to exposure to sublethal doses of metronidazole. BF638R3281 was interrupted by single cross-over gene-specific insertion mutation, and the gene disruption was confirmed by PCR and DNAsequencing analysis. The mutant grew more slowly than the wild type, and the mutation rendered B. fragilis more sensitive to metronidazole and mitomycin C. This indicates that the BF638R3281 gene product plays a role in the survival of B. fragilis following DNA damage by these agents

Propionibacterium acnes in human health and disease

Editoria

An expanded multilocus sequence typing scheme for propionibacterium acnes : investigation of 'pathogenic', 'commensal' and antibiotic resistant strains

The Gram-positive bacterium Propionibacterium acnes is a member of the normal human skin microbiota and is associated with various infections and clinical conditions. There is tentative evidence to suggest that certain lineages may be associated with disease and others with health. We recently described a multilocus sequence typing scheme (MLST) for P. acnes based on seven housekeeping genes (http://pubmlst.org/pacnes). We now describe an expanded eight gene version based on six housekeeping genes and two ‘putative virulence’ genes (eMLST) that provides improved high resolution typing (91eSTs from 285 isolates), and generates phylogenies congruent with those based on whole genome analysis. When compared with the nine gene MLST scheme developed at the University of Bath, UK, and utilised by researchers at Aarhus University, Denmark, the eMLST method offers greater resolution. Using the scheme, we examined 208 isolates from disparate clinical sources, and 77 isolates from healthy skin. Acne was predominately associated with type IA1 clonal complexes CC1, CC3 and CC4; with eST1 and eST3 lineages being highly represented. In contrast, type IA2 strains were recovered at a rate similar to type IB and II organisms. Ophthalmic infections were predominately associated with type IA1 and IA2 strains, while type IB and II were more frequently recovered from soft tissue and retrieved medical devices. Strains with rRNA mutations conferring resistance to antibiotics used in acne treatment were dominated by eST3, with some evidence for intercontinental spread. In contrast, despite its high association with acne, only a small number of resistant CC1 eSTs were identified. A number of eSTs were only recovered from healthy skin, particularly eSTs representing CC72 (type II) and CC77 (type III). Collectively our data lends support to the view that pathogenic versus truly commensal lineages of P. acnes may exist. This is likely to have important therapeutic and diagnostic implications

Smoking Cessation Through Optimisation of Clinical Care in Pregnancy: the STOP randomised controlled trial

This is a pragmatic randomised controlled trial of a dedicated smoking cessation clinic versus routine antenatal care as an intervention to reduce cigarette smoking behaviour. Smoking mothers randomised to the Smoking cessation Through Optimisation of clinical care in Pregnancy (STOP) clinic will have all antenatal care provided by a team comprising an obstetrician, a midwife, and a smoking cessation practitioner. This intervention includes ultrasound screening for fetal growth restriction. The control arm comprises two groups: one receiving standard care with ultrasound screening for fetal growth restriction, and one receiving standard care with ultrasound screening for growth restriction only if clinically indicated by their healthcare provider. Four hundred and fifty women will be recruited and randomised to either intervention or control arms stratifying for age, parity, and history of fetal growth restriction

Mood disorders in childhood and adolescence

The identification and treatment of mood disorders in children and adolescents has grown over the last decades. Major depression is one of the most common and debilitating disorders worldwide, imposing a massive burden to the youth population. Bipolar disorder is being increasingly recognized as having its roots early in life, and its presentation during childhood and adolescence has been submitted to extensive research. This review aims to highlight clinical aspects of the current knowledge on mood disorders in the pediatric population, presenting updated information on epidemiology, diagnostic procedures, and management strategies. Limitations of available evidence and future directions of research in the field are also discussed.Universidade Federal do Rio Grande do Sul Hospital de Clinicas de Porto Alegre Department of PsychiatryUniversidade Federal de São Paulo (UNIFESP) Department of Psychiatry Child and Adolescent Psychiatry UnitUNIFESP, Department of Psychiatry Child and Adolescent Psychiatry UnitSciEL

Marcellus Shale: Cementing and Well Casing Violations

Natural gas extracted from shale formations is one of the fastest growing sources of energy in the United States. Our IQP analyzes public data regarding regulatory violations related to the casing and cementing of shale gas extraction wells in the state of Pennsylvania. Computer based data analysis programs including Microsoft Excel and MATLAB were used to generate visual representations of the data, which allowed our group the ability to more easily identify trends. Our group also interviewed experts on the shale gas industry in order to gain a more complete understanding of the issues at hand. After these interviews and a thorough analysis of the available data, our group recognized and provided explanations for trends in the data