500 research outputs found
Adaptive estimation of an additive regression function from weakly dependent data
A -dimensional nonparametric additive regression model with dependent
observations is considered. Using the marginal integration technique and
wavelets methodology, we develop a new adaptive estimator for a component of
the additive regression function. Its asymptotic properties are investigated
via the minimax approach under the risk over Besov balls. We
prove that it attains a sharp rate of convergence which turns to be the one
obtained in the \iid case for the standard univariate regression estimation
problem.Comment: Substantial improvement of the estimator and the main theore
Analysis of the rod-drop experiments performed during the CABRI commissioning tests
International audienceCABRI is an experimental pulse reactor operated by the CEA at the Cadarache research center. After its refurbishment, it is now able to provide experiments in prototypical PWR conditions (155 bar, 300DC). Before operating, commissioning tests were performed, including control rod worth measurements. These experi-ments are done thanks to the rod-drop technique, which gathers static and dynamic effects. This paper reminds the theoretical background of the rod drop analysis. Then it gives a rigorous definition for the MSM factors (i.e. spatial correction factors to take into account the modification of the detector efficiency). An uncertainty analysis is performed and results prove the validity of the proposed model. Finally, the conclusion focuses on some possible improvements, like a rigorous importance calculation using the stochastic code TRIPOLI-4 and the use of different nuclear data libraries
Osteoid Osteoma of the Capitate: A Case Report and Literature Review
Osteoid osteoma is a benign bone tumor that rarely affects the carpal bones. Because of its nonspecific presentation in the wrist, it remains a diagnostic challenge. We report an unusual case of osteoid osteoma in the capitate where the diagnosis was delayed and the presentation was that of an aggressive natured lesion with considerable functional incapacitation. Diagnosis was made by computed tomographic scan of the wrist and surgical excision lead to a dramatic relief of symptoms
Improved myocardial scar visualization with fast free-breathing motion-compensated black-blood T<sub>1</sub>-rho-prepared late gadolinium enhancement MRI.
Clinical guidelines recommend the use of bright-blood late gadolinium enhancement (BR-LGE) for the detection and quantification of regional myocardial fibrosis and scar. This technique, however, may suffer from poor contrast at the blood-scar interface, particularly in patients with subendocardial myocardial infarction. The purpose of this study was to assess the clinical performance of a two-dimensional black-blood LGE (BL-LGE) sequence, which combines free-breathing T <sub>1</sub> -rho-prepared single-shot acquisitions with an advanced non-rigid motion-compensated patch-based reconstruction.
Extended phase graph simulations and phantom experiments were performed to investigate the performance of the motion-correction algorithm and to assess the black-blood properties of the proposed sequence. Fifty-one patients (37 men, 14 women; mean age, 55 ± 15 [SD] years; age range: 19-81 years) with known or suspected cardiac disease prospectively underwent free-breathing T <sub>1</sub> -rho-prepared BL-LGE imaging with inline non-rigid motion-compensated patch-based reconstruction at 1.5T. Conventional breath-held BR-LGE images were acquired for comparison purposes. Acquisition times were recorded. Two readers graded the image quality and relative contrasts were calculated. Presence, location, and extent of LGE were evaluated.
BL-LGE images were acquired with full ventricular coverage in 115 ± 25 (SD) sec (range: 64-160 sec). Image quality was significantly higher on free-breathing BL-LGE imaging than on its breath-held BR-LGE counterpart (3.6 ± 0.7 [SD] [range: 2-4] vs. 3.9 ± 0.2 [SD] [range: 3-4]) (P <0.01) and was graded as diagnostic for 44/51 (86%) patients. The mean scar-to-myocardium and scar-to-blood relative contrasts were significantly higher on BL-LGE images (P < 0.01 for both). The extent of LGE was larger on BL-LGE (median, 5 segments [IQR: 2, 7 segments] vs. median, 4 segments [IQR: 1, 6 segments]) (P < 0.01), the method being particularly sensitive in segments with LGE involving the subendocardium or papillary muscles. In eight patients (16%), BL-LGE could ascertain or rule out a diagnosis otherwise inconclusive on BR-LGE.
Free-breathing T <sub>1</sub> -rho-prepared BL-LGE imaging with inline motion compensated reconstruction offers a promising diagnostic technology for the non-invasive assessment of myocardial injuries
Environmental influences on familial discordance of phenotype in people with homocystinuria: a case report
<p>Abstract</p> <p>Introduction</p> <p>Non-heritable factors may have an influence on the clinical expression of monogenic inherited metabolic diseases.</p> <p>Case presentation</p> <p>This is a case report of a man whose mother had been diagnosed late in childhood with pyridoxine responsive homocystinuria with lens dislocation and neurodevelopmental delay. These severe complications were not observed in her son who was pyridoxine unresponsive but who had been treated appropriately since early infancy.</p> <p>Conclusion</p> <p>The phenotype of people with homocystinuria can be discordant within a family, with variability in metabolic and clinical expression depending upon both the genotype and therapeutic interventions. Offspring of people with homocystinuria should be screened in early infancy and, if positive, treated appropriately whether they have pyridoxine responsive or unresponsive disease.</p
Undiagnosed Phenylketonuria Can Exist Everywhere:Results From an International Survey
Many countries do not have a newborn screening (NBS) program, and immigrants from such countries are at risk for late diagnosis of phenylketonuria (PKU). In this international survey, 52 of 259 patients (20%) with late diagnosed PKU were immigrants, and 145 of the 259 (55%) were born before NBS or in a location without NBS
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