243 research outputs found
An agglomeration-based massively parallel non-overlapping additive Schwarz preconditioner for high-order discontinuous Galerkin methods on polytopic grids
In this article we design and analyze a class of two-level non-overlapping
additive Schwarz preconditioners for the solution of the linear system of
equations stemming from discontinuous Galerkin discretizations of second-order
elliptic partial differential equations on polytopic meshes. The preconditioner
is based on a coarse space and a non-overlapping partition of the computational
domain where local solvers are applied in parallel. In particular, the coarse
space can potentially be chosen to be non-embedded with respect to the finer
space; indeed it can be obtained from the fine grid by employing agglomeration
and edge coarsening techniques. We investigate the dependence of the condition
number of the preconditioned system with respect to the diffusion coefficient
and the discretization parameters, i.e., the mesh size and the polynomial
degree of the fine and coarse spaces. Numerical examples are presented which
confirm the theoretical bounds
Eziopatogenesi virale (HCV) nel determinismo dell'aborto ricorrente (ripetuto ed abituale)
L’aborto ricorrente può essere definito come la presenza di due (aborto ripetuto) o più aborti (aborto abituale) di tipo consecutivo. Diverse condizioni possono essere individuate come fattori eziopatogenetici di aborto ricorrente; tuttavia, circa la metà dei casi rimane ancora senza causa apparente (aborto “sine causa”).Nel nostro studio sono state inserite 350 donne in stato di gravidanza
con storia clinica di aborto ricorrente, le quali sono state studiate in riferimento all’infezione da HCV.
Delle 350 donne esaminate, 65 (18,6%) sono risultate positive per tale infezione. In particolare, 53 (81%) hanno presentato una positivitĂ della viremia compresa tra 105 e 106 copie/ml; mentre, le restanti 12 (19%) hanno evidenziato
una positivitĂ della viremia > 106 copie/ml.
Pertanto, l’interessamento del prodotto del concepimento da parte dell’HCV potrebbe essere suggestivo di un significativo aspetto eziopatogenetico nel determinismo dell’aborto ricorrente
Understanding Global Change: From Documentation and Collaboration to Social Transformation
The conclusion to the book situates the chapters within four programs of anthropological research on climate change: (1) documentation of local impacts of and adaptations to climate change, (2) connections to socioeconomic and political contexts, (3) collaborations with nonanthropologists, and (4) activism and social transformation. The final section notes the persistent challenges to creating positive change and meaningful research outcomes. It highlights some examples of success and outlines future directions for politically engaged anthropological work around climate change
Sodium Trends in Selected U.S. Total Diet Study Foods, 2003-2011
AbstractObjectiveCharacterize trends in sodium concentrations in the general categories of foods analyzed in the U.S. FDA Total Diet Study (TDS) program from 2003 through 2011. Methods: Trends were assessed for sodium concentrations in a small convenience sample of TDS foods from 2003 to 2011 using simple linear regression with the SAS regression procedure, focusing on sodium concentrations in foods in USDA's sentinel food categories. Results: Levels of sodium in various TDS foods varied over time. Overall, 75 TDS foods did not have statistically significant linear changes in sodium content during that time, and 23 TDS foods did. Certain sentinel foods such as ramen-style noodles showed gradually increasing sodium content from 2003 through 2011. Significance: Over three quarters of foods show no statistically significant linear changes over time. Although a number of selected foods had a statistically significant decline, a limitation to this study is that specific brands of TDS foods were not necessarily the same for each period. The results suggest that some sodium reduction has been occurring in some foods and supports the idea that commercially viable reductions are possible. Such reductions in the sodium content of foods could have large public health implications—rates of hypertension and related health consequences would likely decline—thus saving thousands of lives and billions of dollars each year
Assessing Photoreceptor Structure Associated with Ellipsoid Zone Disruptions Visualized with Optical Coherence Tomography
Purpose: To compare images of photoreceptor layer disruptions obtained with optical coherence tomography (OCT) and adaptive optics scanning light ophthalmoscopy (AOSLO) in a variety of pathologic states.Methods: Five subjects with photoreceptor ellipsoid zone disruption as per OCT and clinical diagnoses of closed-globe blunt ocular trauma (n = 2), macular telangiectasia type 2 (n = 1), blue-cone monochromacy (n = 1), or cone-rod dystrophy (n = 1) were included. Images were acquired within and around photoreceptor lesions using spectral domain OCT, confocal AOSLO, and split-detector AOSLO.Results: There were substantial differences in the extent and appearance of the photoreceptor mosaic as revealed by confocal AOSLO, split-detector AOSLO, and spectral domain OCT en face view of the ellipsoid zone.Conclusion: Clinically available spectral domain OCT, viewed en face or as B-scan, may lead to misinterpretation of photoreceptor anatomy in a variety of diseases and injuries. This was demonstrated using split-detector AOSLO to reveal substantial populations of photoreceptors in areas of no, low, or ambiguous ellipsoid zone reflectivity with en face OCT and confocal AOSLO. Although it is unclear if these photoreceptors are functional, their presence offers hope for therapeutic strategies aimed at preserving or restoring photoreceptor function
FlorItaly-the portal to the flora of Italy
Digital data concerning the flora of Italy are largely fragmented among different resources hosted on different platforms, and often with different data standards, which are neither connected by a common access point, nor by web services, thus constituting a relevant obstacle to data access and usage. Taxonomic incongruences add a further complication. This paper describes "FlorItaly", an online information system which allows to access and query updated information on the checklist of the flora of Italy, aiming at becoming an aggregator for Italian botanical resources. "FlorItaly" was developed in a collaborative effort by more than 50 taxonomists, with the support of the Italian Botanical Society, and of Project "Dryades" (University of Trieste), to provide a better and reliable organization of botanical knowledge in Italy, as well as a relevant simplification for data retrieval, and a further stimulus towards a more collaborative approach in botanical research
Overcoming the Challenges to Clinical Development of X-Linked Retinitis Pigmentosa Therapies: Proceedings of an Expert Panel
UNLABELLED: X-linked retinitis pigmentosa (XLRP) is a rare inherited retinal disease manifesting as impaired night vision and peripheral vision loss that progresses to legal blindness. Although several trials of ocular gene therapy for XLRP have been conducted or are in progress, there is currently no approved treatment. In July 2022, the Foundation Fighting Blindness convened an expert panel to examine relevant research and make recommendations for overcoming the challenges and capitalizing on the opportunities in conducting clinical trials of RPGR-targeted therapy for XLRP. Data presented concerned RPGR structure and mutation types known to cause XLRP, RPGR mutation-associated retinal phenotype diversity, patterns in genotype/phenotype relationships, disease onset and progression from natural history studies, and the various functional and structural tests used to monitor disease progression. Panel recommendations include considerations, such as genetic screening and other factors that can impact clinical trial inclusion criteria, the influence of age on defining and stratifying participant cohorts, the importance of conducting natural history studies early in clinical development programs, and the merits and drawbacks of available tests for measuring treatment outcomes. We recognize the need to work with regulators to adopt clinically meaningful end points that would best determine the efficacy of a trial. Given the promise of RPGR-targeted gene therapy for XLRP and the difficulties encountered in phase III clinical trials to date, we hope these recommendations will help speed progress to finding a cure.
TRANSLATIONAL RELEVANCE: Examination of relevant data and recommendations for the successful clinical development of gene therapies for RPGR-associated XLRP
Repeatability and Longitudinal Assessment of Foveal Cone Structure in Cngb3-associated Achromatopsia
PURPOSE: Congenital achromatopsia is an autosomal recessive disease causing substantial reduction or complete absence of cone function. Although believed to be a relatively stationary disorder, questions remain regarding the stability of cone structure over time. In this study, the authors sought to assess the repeatability of and examine longitudinal changes in measurements of central cone structure in patients with achromatopsia. METHODS: Forty-one subjects with CNGB3-associated achromatopsia were imaged over a period of between 6 and 26 months using optical coherence tomography and adaptive optics scanning light ophthalmoscopy. Outer nuclear layer (ONL) thickness, ellipsoid zone (EZ) disruption, and peak foveal cone density were assessed. RESULTS: ONL thickness increased slightly compared with baseline (0.184 μm/month, P = 0.02). The EZ grade remained unchanged for 34/41 subjects. Peak foveal cone density did not significantly change over time (mean change 1% per 6 months, P = 0.126). CONCLUSION: Foveal cone structure showed little or no change in this group of subjects with CNGB3-associated achromatopsia. Over the time scales investigated (6–26 months), achromatopsia seems to be a structurally stable condition, although longer-term follow-up is needed. These data will be useful in assessing foveal cone structure after therapeutic intervention
Residual Foveal Cone Structure in CNGB3-Associated Achromatopsia
PURPOSE: Congenital achromatopsia (ACHM) is an autosomal recessive disorder in which cone function is absent or severely reduced. Gene therapy in animal models of ACHM have shown restoration of cone function, though translation of these results to humans relies, in part, on the presence of viable cone photoreceptors at the time of treatment. Here, we characterized residual cone structure in subjects with CNGB3-associated ACHM. METHODS: High-resolution imaging (optical coherence tomography [OCT] and adaptive optics scanning light ophthalmoscopy [AOSLO]) was performed in 51 subjects with CNGB3-associated ACHM. Peak cone density and inter-cone spacing at the fovea was measured using split-detection AOSLO. Foveal outer nuclear layer thickness was measured in OCT images, and the integrity of the photoreceptor layer was assessed using a previously published OCT grading scheme RESULTS: Analyzable images of the foveal cones were obtained in 26 of 51 subjects, with nystagmus representing the major obstacle to obtaining high-quality images. Peak foveal cone density ranged from 7,273 to 53,554 cones/mm2, significantly lower than normal (range, 84,733–234,391 cones/mm2), with the remnant cones being either contiguously or sparsely arranged. Peak cone density was correlated with OCT integrity grade; however, there was overlap of the density ranges between OCT grades. CONCLUSIONS: The degree of residual foveal cone structure varies greatly among subjects with CNGB3-associated ACHM. Such measurements may be useful in estimating the therapeutic potential of a given retina, providing affected individuals and physicians with valuable information to more accurately assess the risk-benefit ratio as they consider enrolling in experimental gene therapy trials. (www.clinicaltrials.gov, NCT01846052.
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