480 research outputs found

    Comparação de tamanhos de quadrats na amostragem do bivalve não-nativo Corbicula fluminea (Müller, 1774) (Bivalvia: Corbiculidae)

    Get PDF
    We aimed to designate which is the best quadrat area to be used in sampling of C. fluminea for determination of their population parameters. The quadrat of 0.0625 m2 showed the best cost efficiency and a lowest sampling effort, being recommended for study of C. fluminea in lentic environments.Nós indicamos qual é a melhor área de quadrat a ser utilizada na amostragem de C. fluminea para determinação de seus parâmetros populacionais. O quadrat de 0,0625 m2 apresentou o melhor custo-benefício e um menor esforço amostral, sendo recomendado para estudo de C. fluminea em ambientes lênticos.Facultad de Ciencias Naturales y Muse

    Investigating poisson noise filtering in Digital Breast Tomosynthesis

    Get PDF
    Digital Breast Tomosynthesis (DBT) is a potential\ud candidate to substitute digital mammography in breast cancer\ud screening. In DBT, projection images are acquired with low\ud levels of radiation, which significantly increases image noise. In\ud this work, we evaluate the effect of a denoising filter, designed for\ud digital mammography, on the reduction of quantum noise in\ud DBT images. This filter is based on an adaptive Wiener filter and\ud the Anscombe transformation, to reduce Poisson noise without\ud significantly affecting image sharpness. Denoising was applied to\ud a set of synthetic DBT images generated using a 3D\ud anthropomorphic software breast phantom. Images without noise\ud was also created to provide ground-truth information. In order to\ud evaluate the denoising performance in different steps of the DBT\ud imaging, filtering was applied separately to the projections\ud (before reconstruction) and to the tomographic slices (after\ud reconstruction). The performance of the filter was evaluated\ud considering qualitative and quantitative analysis of the images\ud before and after denoising.FAPESPCNP

    Interventions for physical activity promotion applied to the primary healthcare settings for people living in regions of low socioeconomic level: study protocol for a non-randomized controlled trial.

    Get PDF
    BACKGROUND: Regular physical activity practice has been widely recommended for promoting health, but the physical activity levels remain low in the population. Therefore, the study of interventions to promote physical activity is essential. OBJECTIVE: To present the methodology of two physical activity interventions from the "Ambiente Ativo" ("Active Environment") project. METHODS: 12-month non-randomized controlled intervention trial. 157 healthy and physically inactive individuals were selected: health education (n = 54) supervised exercise (n = 54) and control (n = 49). Intervention based on health education: a multidisciplinary team of health professionals organized the intervention in group discussions, phone calls, SMS and educational material. Intervention based on supervised exercise program: consisted of offering an exercise program in groups supervised by physical education professionals involving strength, endurance and flexibility exercises. The physical activity level was assessed by the International Physical Activity Questionnaire (long version), physical activities recalls, pedometers and accelerometers over a seven-day period. RESULT: This study described two different proposals for promoting physical activity that were applied to adults attended through the public healthcare settings. The participants were living in a region of low socioeconomic level, while respecting the characteristics and organization of the system and its professionals, and also adapting the interventions to the realities of the individuals attended. CONCLUSION: Both interventions are applicable in regions of low socioeconomic level, while respecting the social and economic characteristics of each region. TRIAL REGISTRATION: ClinicalTrials.gov NCT01852981

    Effect of denoising on the quality of reconstructed images in digital breast tomosynthesis

    Get PDF
    Individual projection images in Digital Breast Tomosynthesis (DBT) must be acquired with low levels of radiation,\ud which significantly increases image noise. This work investigates the influence of a denoising algorithm and the\ud Anscombe transformation on the reduction of quantum noise in DBT images. The Anscombe transformation is a\ud variance-stabilizing transformation that converts the signal-dependent quantum noise to an approximately signalindependent\ud Gaussian additive noise. Thus, this transformation allows for the use of conventional denoising algorithms,\ud designed for additive Gaussian noise, on the reduction of quantum noise, by working on the image in the Anscombe\ud domain. In this work, denoising was performed by an adaptive Wiener filter, previously developed for 2D\ud mammography, which was applied to a set of synthetic DBT images generated using a 3D anthropomorphic software\ud breast phantom. Ideal images without noise were also generated in order to provide a ground-truth reference. Denoising\ud was applied separately to DBT projections and to the reconstructed slices. The relative improvement in image quality\ud was assessed using objective image quality metrics, such as peak signal-to-noise ratio (PSNR) and mean structural\ud similarity index (SSIM). Results suggest that denoising works better for tomosynthesis when using the Anscombe\ud transformation and when denoising was applied to each projection image before reconstruction; in this case, an average\ud increase of 9.1 dB in PSNR and 58.3% in SSIM measurements was observed. No significant improvement was observed\ud by using the Anscombe transformation when denoising was applied to reconstructed images, suggesting that the\ud reconstruction algorithm modifies the noise properties of the DBT images.FAPESPCNP

    Drug Adverse Event Detection in Health Plan Data Using the Gamma Poisson Shrinker and Comparison to the Tree-based Scan Statistic

    Get PDF
    Background: Drug adverse event (AE) signal detection using the Gamma Poisson Shrinker (GPS) is commonly applied in spontaneous reporting. AE signal detection using large observational health plan databases can expand medication safety surveillance. Methods: Using data from nine health plans, we conducted a pilot study to evaluate the implementation and findings of the GPS approach for two antifungal drugs, terbinafine and itraconazole, and two diabetes drugs, pioglitazone and rosiglitazone. We evaluated 1676 diagnosis codes grouped into 183 different clinical concepts and four levels of granularity. Several signaling thresholds were assessed. GPS results were compared to findings from a companion study using the identical analytic dataset but an alternative statistical method—the tree-based scan statistic (TreeScan). Results: We identified 71 statistical signals across two signaling thresholds and two methods, including closely-related signals of overlapping diagnosis definitions. Initial review found that most signals represented known adverse drug reactions or confounding. About 31% of signals met the highest signaling threshold. Conclusions: The GPS method was successfully applied to observational health plan data in a distributed data environment as a drug safety data mining method. There was substantial concordance between the GPS and TreeScan approaches. Key method implementation decisions relate to defining exposures and outcomes and informed choice of signaling thresholds

    Black hole thermodynamical entropy

    Full text link
    As early as 1902, Gibbs pointed out that systems whose partition function diverges, e.g. gravitation, lie outside the validity of the Boltzmann-Gibbs (BG) theory. Consistently, since the pioneering Bekenstein-Hawking results, physically meaningful evidence (e.g., the holographic principle) has accumulated that the BG entropy SBGS_{BG} of a (3+1)(3+1) black hole is proportional to its area L2L^2 (LL being a characteristic linear length), and not to its volume L3L^3. Similarly it exists the \emph{area law}, so named because, for a wide class of strongly quantum-entangled dd-dimensional systems, SBGS_{BG} is proportional to lnL\ln L if d=1d=1, and to Ld1L^{d-1} if d>1d>1, instead of being proportional to LdL^d (d1d \ge 1). These results violate the extensivity of the thermodynamical entropy of a dd-dimensional system. This thermodynamical inconsistency disappears if we realize that the thermodynamical entropy of such nonstandard systems is \emph{not} to be identified with the BG {\it additive} entropy but with appropriately generalized {\it nonadditive} entropies. Indeed, the celebrated usefulness of the BG entropy is founded on hypothesis such as relatively weak probabilistic correlations (and their connections to ergodicity, which by no means can be assumed as a general rule of nature). Here we introduce a generalized entropy which, for the Schwarzschild black hole and the area law, can solve the thermodynamic puzzle.Comment: 7 pages, 2 figures. Accepted for publication in EPJ

    Physical activity promotion by health practitioners: a distance-learning training component to improve knowledge and counseling

    Get PDF
    Aim To report an evaluation of health professionals' participation in a distance-learning physical activity training course developed in a low socio-economic region of São Paulo city, Brazil. BACKGROUND In countries with public universal health systems, physical activity promotion in primary health care settings can reap results, particularly given that such interventions have the potential to reach a large percentage of the population. However, few studies proposed physical activity training for health professionals in low- and middle-income countries. Brazil is a continental country and has the Unified Health System which incorporates family health teams in over 85% of Brazilian cities. METHODS The physical activity training was part of the fifth module of an educational intervention throughout a distance-learning course focusing on health professionals at M'Boi Mirim district in São Paulo city. The training totaled 3 h and had five themes of physical activity: (1) concepts, definitions benefits; (2) evaluation; (3) recommendation; (4) interventions; (5) physical activity counseling. The opinion of health professionals was evaluated after training by two open questions. Findings Out of 106 professionals who took part of the course, only 22.6% (n=24) had accessed the fifth module. These professionals were predominantly female (79.2%), nurses (66.7%) and aged 30 years or older. Responses highlighted the course approach focused on physical activity for improving patient's quality of life and well-being, disease prevention and health improvements. Regarding the themes for improvement, the health professionals identified that there was a need to experience physical activity classes first-hand, and the need to link physical activity counseling to the local venues that provide structured physical activity programs. We recommend that further training courses can be conducted based on this model for health professionals to promote physical activity to the community in Brazil

    Angiosarcoma of the nasal cavity: a case report

    Get PDF
    Angiosarcomas are malignant neoplasias of rapid growth that develop from endothelial cells. They represent 2% of all sarcomas and only 1–4% are located in the aerodigestive tract. Since 1977, only 16 cases have been reported
    corecore