4,733 research outputs found

    Gravitino perturbations in Schwarzschild black holes

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    We consider the time evolution of massless gravitino perturbations in Schwarzschild black holes, and show that as in the case of fields of other values of spin, the evolution comes in three stages, after an initial outburst as a first stage, we observe the damped oscillations characteristic of the quasinormal ringing stage, followed by long time tails. Using the sixth order WKB method and Prony fitting of time domain data we determine the quasinormal frequencies. There is a good correspondence between the results obtained by the above two methods, and we obtain a considerable improvement with respect to the previously obtained third order WKB results. We also show that the response of a black hole depends crucially on the spin class of the perturbing field: the quality factor becomes a decreasing function of the spin for boson perturbations, whereas the opposite situation appears for fermion ones

    BisoGenet: a new tool for gene network building, visualization and analysis

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    <p>Abstract</p> <p>Background</p> <p>The increasing availability and diversity of omics data in the post-genomic era offers new perspectives in most areas of biomedical research. Graph-based biological networks models capture the topology of the functional relationships between molecular entities such as gene, protein and small compounds and provide a suitable framework for integrating and analyzing omics-data. The development of software tools capable of integrating data from different sources and to provide flexible methods to reconstruct, represent and analyze topological networks is an active field of research in bioinformatics.</p> <p>Results</p> <p>BisoGenet is a multi-tier application for visualization and analysis of biomolecular relationships. The system consists of three tiers. In the data tier, an in-house database stores genomics information, protein-protein interactions, protein-DNA interactions, gene ontology and metabolic pathways. In the middle tier, a global network is created at server startup, representing the whole data on bioentities and their relationships retrieved from the database. The client tier is a Cytoscape plugin, which manages user input, communication with the Web Service, visualization and analysis of the resulting network.</p> <p>Conclusion</p> <p>BisoGenet is able to build and visualize biological networks in a fast and user-friendly manner. A feature of Bisogenet is the possibility to include coding relations to distinguish between genes and their products. This feature could be instrumental to achieve a finer grain representation of the bioentities and their relationships. The client application includes network analysis tools and interactive network expansion capabilities. In addition, an option is provided to allow other networks to be converted to BisoGenet. This feature facilitates the integration of our software with other tools available in the Cytoscape platform. BisoGenet is available at <url>http://bio.cigb.edu.cu/bisogenet-cytoscape/</url>.</p

    Epidemiología de las fracturas de la extremidad proximal del fémur en asturias

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    Hemos realizado un estudio epidemiológico de las fracturas de fémur proximal en personas mayores de 50 años, atendidas en nuestro Hospital durante los años 1990-92. Se valoraron un total de 355 casos. En el período estudiado se observó que las fracturas más numerosas fueron la cervicales, no encontrando diferencias significativas en los ingresos según el período estacional. La edad media de presentación fue de 81 años. La tasa de incidencia fue muy semejante a las otras provincias españolas y menor que la encontrada en los países del Norte de Europa, Inglaterra y Estados Unidos.We have performed an epidemiologic study on the incidence of proximal femoral fractures in patients older than 50 years, all reviewed in our Hospital from 1990 to 1992. We included 355 patients. Femoral neek fractures were the most frequent lesions. No significant differences in the hospital admissions were found during all the year's seasons. The mean age of presentation was 81 years. The incidence rate was similar to the rest of Spain, and less than in North Europe, England and United States

    Study of the quality of fruits of the Hylocereusundatus (Haw) Britton Rose and Hylocereusmegalanthus(K. Schum ex Vaupel) Ralf Baue (Red and Yellow Pitahaya) during the maturationperiod

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    In this work, the organoleptic and sensorial characteristics were determined, as well as the maturation pattern of the yellow and red pitahaya fruits grown in Ecuador. Several fruit quality indexes were evaluated for 15 days from the moment of harvest, such as: weight loss, dry matter, total soluble solids, titratable acidity, exocarp coloration and maturity relationship and related damages by attack of biotic agents. The results indicated that in storage conditions with a temperature of 25 ± 1 ° C, the red pitahaya presents a gradual loss of fruit quality up to nine days; after this period serious fungal damage to the fruit that affects its commercial quality begins. The yellow pitahaya has a time of storage that can reach up to 15 days, although the fruit looks externally dehydrated and aged; however internally the fruit maintains its quality for consumption. It presents organosensitive standards of quality and resistance to microbiological agents superior to those of the red pitahaya. Due to the behavior of the fruit in the various variables evaluated in this study, strong evidences are presented that suggest to consider it as a species of non-climacteric respiration

    Bound - states for truncated Coulomb potentials

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    The pseudoperturbative shifted - ll expansion technique PSLET is generalized for states with arbitrary number of nodal zeros. Bound- states energy eigenvalues for two truncated coulombic potentials are calculated using PSLET. In contrast with shifted large-N expansion technique, PSLET results compare excellently with those from direct numerical integration.Comment: TEX file, 22 pages. To appear in J. Phys. A: Math. & Ge

    Prevalence of juvenile idiophatic arthritis in Colombia

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    To estimate the prevalence of Juvenile Idiophatic Arthritis (JIA) in Colombia. This cross-sectional study identified patients with a diagnosis code for AIJ (ICD-10 M08-M09) using a nationally-representative database of health care resource utilization provided by the “Sistema Integral de Información de la Protección Social (SISPRO)” in 2017. In addition, estimated prevalence was contrasted using data of personal history of JIA using a database of patients with ≤ 16 years affiliated to a subsidized-regime insurance company (N = 397,160) of the Caribbean region of Colombia. The estimated prevalences were extrapolated to the overall Colombian population using the demographic projections of individuals with ≤ 16 years of age (14,588,845) provided by the Departamento Administrativo Nacional de Estadisticas (DANE). In 2017, the prevalence of JIA in the subsidized-regime company was 13 per 100,000 (52/397.160). According to the data of SISPRO the prevalence of JIA in Colombia was 10.9 per 100,000 (1,602/14,588,845). Extrapolating these estimations to the general population of Colombia, the estimated number of prevalent cases of JIA in Colombia could be approximately 1.602 and 1.896 cases, respectively. These estimations are lower in Colombia compared to previously reported prevalence globally (between 60 and 400 cases per 100,000)

    Vacuum polarization effects on quasinormal modes in electrically charged black hole spacetimes

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    We investigate the influence of vacuum polarization of quantum massive fields on the scalar sector of quasinormal modes in spherically symmetric black holes. We consider the evolution of a massless scalar field on the spacetime corresponding to a charged semiclassical black hole, consisting of the quantum corrected geometry of a Reissner-Nordstr\"om black hole dressed by a quantum massive scalar field in the large mass limit. Using a sixth order WKB approach we find the shift in the quasinormal mode frequencies due to vacuum polarization .Comment: 9 pages, 5 figures, typos added, references added and content change

    Stain-free identification of tissue pathology using a generative adversarial network to infer nanomechanical signatures

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    Intraoperative frozen section analysis can be used to improve the accuracy of tumour margin estimation during cancer resection surgery through rapid processing and pathological assessment of excised tissue. Its applicability is limited in some cases due to the additional risks associated with prolonged surgery, largely from the time-consuming staining procedure. Our work uses a measurable property of bulk tissue to bypass the staining process: as tumour cells proliferate, they influence the surrounding extra-cellular matrix, and the resulting change in elastic modulus provides a signature of the underlying pathology. In this work we accurately localise atomic force microscopy measurements of human liver tissue samples and train a generative adversarial network to infer elastic modulus from low-resolution images of unstained tissue sections. Pathology is predicted through unsupervised clustering of parameters characterizing the distributions of inferred values, achieving 89% accuracy for all samples based on the nominal assessment (n = 28), and 95% for samples that have been validated by two independent pathologists through post hoc staining (n = 20). Our results demonstrate that this technique could increase the feasibility of intraoperative frozen section analysis for use during resection surgery and improve patient outcomes

    Association between IL-18 gene polymorphisms and biopsy-proven giant cell arteritis

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    7 pages, 1 figure, 1 table.-- Research article.[Introduction] The objective was to investigate the potential implication of the IL18 gene promoter polymorphisms in the susceptibility to giant-cell arteritis (GCA).[Methods] In total, 212 patients diagnosed with biopsy-proven GCA were included in this study. DNA from patients and matched controls was obtained from peripheral blood. Samples were genotyped for the IL18-137 G>C (rs187238), the IL18-607 C>A (rs1946518), and the IL18-1297 T>C (rs360719) gene polymorphisms with polymerase chain reaction, by using a predesigned TaqMan allele discrimination assay.[Results] No significant association between the IL18-137 G>C polymorphism and GCA was found. However, the IL18 -607 allele A was significantly increased in GCA patients compared with controls (47.8% versus 40.9% in patients and controls respectively; P = 0.02; OR, 1.32; 95% CI, 1.04 to 1.69). It was due to an increased frequency of homozygosity for the IL18 -607 A/A genotype in patients with GCA (20.4%) compared with controls (13.4%) (IL18 -607 A/A versus IL18 -607 A/C plus IL18 -607 C/C genotypes: P = 0.04; OR, 1.59; 95% CI, 1.02 to 2.46). Also, the IL18-1297 allele C was significantly increased in GCA patients (30.7%) compared with controls (23.0%) (P = 0.003; OR, 1.48; 95% CI, 1.13 to 1.95). In this regard, an increased susceptibility to GCA was observed in individuals carrying the IL18-1297 C/C or the IL18-1297 C/T genotypes compared with those carrying the IL18-1297 T/T genotype (IL18-1297 C/C plus IL18-1297 T/C versus IL18-1297 T/T genotype in GCA patients compared with controls: P = 0.005; OR, 1.61; 95% CI, 1.15 to 2.25). We also found an additive effect of the IL18 -1297 and -607 polymorphisms with TLR4 Asp299Gly polymorphism. The OR for GCA was 1.95 for combinations of genotypes with one or two risk alleles, whereas carriers of three or more risk alleles have an OR of 3.7.[Conclusions] Our results show for the first time an implication of IL18 gene-promoter polymorphisms in the susceptibility to biopsy-proven GCA. In addition, an additive effect between the associated IL18 and TLR4 genetic variants was observed.This study was supported by a grant from Fondo de Investigaciones Sanitarias PI06-0024 (Spain) and in part by Junta de Andalucía, grupo CTS-180 (Spain). This work was partially supported by the RETICS Program, RD08/0075 (RIER), from Instituto de Salud Carlos III (ISCIII).Peer reviewe
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