On the segmentation of astronomical images via level-set methods

Astronomical images are of crucial importance for astronomers since they contain a lot of information about celestial bodies that can not be directly accessible. Most of the information available for the analysis of these objects starts with sky explorations via telescopes and satellites. Unfortunately, the quality of astronomical images is usually very low with respect to other real images and this is due to technical and physical features related to their acquisition process. This increases the percentage of noise and makes more difficult to use directly standard segmentation methods on the original image. In this work we will describe how to process astronomical images in two steps: in the first step we improve the image quality by a rescaling of light intensity whereas in the second step we apply level-set methods to identify the objects. Several experiments will show the effectiveness of this procedure and the results obtained via various discretization techniques for level-set equations.Comment: 24 pages, 59 figures, paper submitte

Evaluation of caries risk in pre-school children using the CAMBRA protocol and CAST index / Avaliação do risco de cárie em crianças em idade pré-escolar utilizando o protocolo CAMBRA e o índice CAST

Objective: To evaluate the risk of caries and oral health condition in children, using the CAMBRA protocol of the American Academy of Pediatric Dentistry (AAPD) and the Species and Treatment Index for Caries Assessment (CAST) in preschoolers. Method: Method: It is characterized as a cross-sectional retrospective observational analytical study, with clinical examination procedures, questionnaires and oral hygiene analysis in children from 2 to 5 years old. 507 preschoolers aged 2 to 5 years were evaluated in public daycare centers in the city of São Gonçalo - Brazil. Results: The CAMBRA protocol has a moderate risk of 55.4%, while 44.6% has a high risk of caries, from 2 to 5 years. When considering the range of 2 to 3 years apart, 67.1% of children are at high risk. The CAST index showed 10.6% of lesions caused by caries, correlated between caries and the CAST index. Conclusion: It is necessary to implement preventive strategies to reduce caries in this studied group

The Regge Limit for Green Functions in Conformal Field Theory

We define a Regge limit for off-shell Green functions in quantum field theory, and study it in the particular case of conformal field theories (CFT). Our limit differs from that defined in arXiv:0801.3002, the latter being only a particular corner of the Regge regime. By studying the limit for free CFTs, we are able to reproduce the Low-Nussinov, BFKL approach to the pomeron at weak coupling. The dominance of Feynman graphs where only two high momentum lines are exchanged in the t-channel, follows simply from the free field analysis. We can then define the BFKL kernel in terms of the two point function of a simple light-like bilocal operator. We also include a brief discussion of the gravity dual predictions for the Regge limit at strong coupling.Comment: 23 pages 2 figures, v2: Clarification of relation of the Regge limit defined here and previous work in CFT. Clarification of causal orderings in the limit. References adde

Obesity and treatment meanings in bariatric surgery candidates: a qualitative study

Background This study used a qualitative approach to comprehend how the morbid obese conceptualize and deal with obesity and obesity treatment, with the particular aim of exploring the expectations and beliefs about the exigencies and the impact of bariatric surgery. Methods The study population included 30 morbid obese patients (20 women and 10 men) with a mean age of 39.17 years (SD = 8.81) and a mean body mass index of 47.5 (SD = 8.2) interviewed individually before surgery using open-ended questions. The interviews were audiotaped, transcribed, and then coded according to grounded analysis methodology. Results Three main thematic areas emerged from the data: obesity, eating behavior, and treatment. Obesity is described as a stable and hereditary trait. Although participants recognize that personal eating behavior exacerbates this condition, patients see their eating behavior as difficult to change and control. Food seems to be an ever-present dimension and a coping strategy, and to follow an adequate diet plan is described as a huge sacrifice. Bariatric surgery emerges as the only treatment for obesity, and participants highlight this moment as the beginning of a new life where health professionals have the main role. Bariatric surgery candidates see their eating behavior as out of their control, and to commit to its demands is seen as a big sacrifice. For these patients, surgery is understood as a miracle moment that will change their lives without requiring an active role or their participation. Conclusion According to these results, it is necessary to validate them with qualitative and quantitative studies; it is necessary to promote a new awareness of the weight loss process and to empower patients before and after bariatric surgery.Bolsa de doutoramento SFRH/BD/37069/2007 da Fundação para a Ciência e a Tecnologia (FCT

Comparison between dmf/DMF and ICDAS in Brazilian schoolchildren: a cross-sectional study / Comparação entre ceo/CPO e ICDAS em escolares brasileiros: um estudo transversal

The objective was to compare the use of the International Caries Detection and Assessment System (ICDAS-II) and the dmft/DMFT (WHO) indexes in epidemiological surveys in schools. Two calibrated examiners analyzed 402 public school children aged 5-12 years, in the city of Mesquita, Rio de Janeiro, Brazil, using ICDAS-II and WHO criteria. The schools are located in areas covered by the Family Health Strategy. The DMF-DMF-S, dmf-t, dmf-s, the prevalence of decayed teeth, and examination time were calculated using both systems. The research subjects participated in health education and prevention activities and oral hygiene training. Data were statistically analyzed and the mean dmf-t / DMF-T was 2.35 (sd ± 2.15) and 3.18 (sd ± 2.31), respectively, using the WHO criteria. When considering the score of the three-ICDASII the average was 2.64 (sd ± 1.89) and 3.45 (sd ± 2.48). With the score-2 ICDASII, 4386 surfaces with lesions were identified, 2795 (63.7%) were not considered when we used the dmf-t / DMF-T. The average examination time was almost twice as long to ICDAS-II (3.2 ± 1.9 min) and WHO (1.8 ± 0.9 min). Conclusion: The ICDAS-II, and provide information on non-cavitated lesions of caries, shows significant experience of dental caries in schoolchildren from the city, and can generate data comparable with previous research that used the WHO criteria

Combinations of motor measures more strongly predict adverse health outcomes in old age: the rush memory and aging project, a community-based cohort study

<p>Abstract</p> <p>Objective</p> <p>Motor impairment in old age is a growing public-health concern, and several different constructs have been used to identify motor impairments in older people. We tested the hypothesis that combinations of motor constructs more strongly predict adverse health outcomes in older people.</p> <p>Methods</p> <p>In total, 949 people without dementia, history of stroke or Parkinson's disease, who were participating in the Rush Memory and Aging Project (a longitudinal community-based cohort study), underwent assessment at study entry. From this, three constructs were derived: 1) physical frailty based on grip strength, timed walk, body mass index and fatigue; 2) Parkinsonian Signs Score based on the modified motor section of the Unified Parkinson's Disease Rating Scale; and 3) a motor construct, based on nine strength measures and nine motor performances. Disability and cognitive status were assessed annually. A series of Cox proportional-hazards models, controlling for age, sex and education, were used to examine the association of each of these three constructs alone and in various combinations with death, disability and Alzheimer's disease (AD).</p> <p>Results</p> <p>All three constructs were related (mean <it>r </it>= 0.50, all <it>P </it>< 0.001), and when considered individually in separate proportional-hazards models, were associated with risk of death, incident disability and AD. However, when considered together, combinations of these constructs more strongly predicted adverse health outcomes.</p> <p>Conclusions</p> <p>Physical frailty, parkinsonian signs score and global motor score are related constructs that capture different aspects of motor function. Assessments using several motor constructs may more accurately identify people at the highest risk of adverse health consequences in old age.</p