601 research outputs found

    Visual Notations in Container Orchestrations: An Empirical Study with Docker Compose

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    Context: Container orchestration tools supporting infrastructure-as-code allow new forms of collaboration between developers and operatives. Still, their text-based nature permits naive mistakes and is more difficult to read as complexity increases. We can find few examples of low-code approaches for defining the orchestration of containers, and there seems to be a lack of empirical studies showing the benefits and limitations of such approaches. Goal & method: We hypothesize that a complete visual notation for Docker-based orchestrations could reduce the effort, the error rate, and the development time. Therefore, we developed a tool featuring such a visual notation for Docker Compose configurations, and we empirically evaluated it in a controlled experiment with novice developers. Results: The results show a significant reduction in development time and error-proneness when defining Docker Compose files, supporting our hypothesis. The participants also thought the prototype easier to use and useful, and wanted to use it in the future

    Short-reach MCF-based systems employing KK Receivers and feedforward neural networks for ICXT mitigation

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    This paper proposes and evaluates the use of machine learning (ML) techniques for mitigating the effect of the random inter-core crosstalk (ICXT) on 256 Gb/s short-reach systems employing weakly coupled multicore fiber (MCF) and Kramers–Kronig (KK) receivers. The performance improvement provided by the k-means clustering, k nearest neighbor (KNN) and feedforward neural network (FNN) techniques are assessed and compared with the system performance obtained without employing ML. The FNN proves to significantly improve the system performance by mitigating the impact of the ICXT on the received signal. This is achieved by employing only 10 neurons in the hidden layer and four input features for the training phase. It has been shown that k-means or KNN techniques do not provide performance improvement compared to the system without using ML. These conclusions are valid for direct detection MCF-based short-reach systems with the product between the skew (relative time delay between cores) and the symbol rate much lower than one (skew×symbol rate≪1). By employing the proposed FNN, the bit error rate (BER) always stood below 10−1.8 on all the time fractions under analysis (compared with 100 out of 626 occurrences above the BER threshold when ML was not used). For the BER threshold of 10−1.8 and compared with the standard system operating without employing ML techniques, the system operating with the proposed FNN shows a received optical power improvement of almost 3 dB.info:eu-repo/semantics/publishedVersio

    Biological response to a bioactive glass coated implant: experimental data

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    A biomaterial constituted by a metallic titanium alloy (TiAl6V4) coated with a bioglass layer (Na2O (7-24%), K2O (2-8%), CaO (9-20%), Al2O3 (0.1-2%), MgO (0.1-2%), SiO2 (46-53%) and P2O5 (4-8%) was implanted in the cancellous bone of adult rabbit knee, in orthotopic situation, under conditions of mechanical stability. The animals were sacrificed after 30 (Group I), 90 (Group II), and 180 (Group III) days postoperatively. The bone pieces, containing the samples under investigation, were studied using radiographs, optical microscopy, scanning electron microscopy and electron probe micro-analysis. Radiologically, osteointegration of the implant surface was observed in all cases at the 180th day after the surgery. A new bone formation was observed in the animals of Group I and the specimens observed after 90 days of the surgery (Group II) presented a higher amount of new bone tissue. At the 180th day, the bioglass coating of the metallic titanium alloy was not detected and a total contact between the metallic surface and the new bone tissue was observed. The incorporation of the bioglass layer into the bone matrix occurred without interposition of non mineralized tissues and without the presence of inflammatory cells. These results strongly suggest that the studied ceramic coating material of the metallic implant is bioactive, biocompatible, bioresorbable, and possess osteoconductive properties

    Contrabando: o jogo do jogo

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    Falarei do contrabando numa perspectiva da memória, sob a forma de histórias de família, contadas e recontadas até se tomarem parte integrante das personagens que as viveram, tomando-se indissociáveis delas. São as histórias vividas pelos avós e pelos pais - mortos ou vivos - mas que lhes conferiram e conferem ainda, uma dimensão especial, de marginalidade quase heróica porque diferente; uma dimensão diversa e aventureira da vida dos indivíduos. Recordam-se, através das vivências dos familiares e amigos, os conhecimentos agora inúteis e inoperantes de rotas e esconderijos por onde passaram mercadorias e onde eram escondidas, os truques usados e as melhores maneiras de cativar as autoridades, dando, aqui e ali as "luvas" da praxe. E recordam-se as sensações - de medo, de satisfação, de competição e o sabor a jogo^ que o contrabando tem nas fugas, nos encontros e nos desencontros entre contrabandistas e autoridades

    Influence of albumin on the tribological behavior of Ag-Ti (C, N) thin films for orthopedic implants

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    With the increase of elderly population and the health problems arising nowadays, such as cancer, knee and hip joint prostheses are widely used worldwide. It is estimated that 20% of hip replacement surgeries simply fail after 5 years, due to wear loosening, instability and infection. In this paper it is reported the study of advanced materials with the ability to overcome some of these drawbacks. The development of ceramic coatings, based on carbonitrides of transition metals, such as TiCN, doped with silver, Ag, may represent an effective solution. Thin films of Ag-TiCN were produced by dc reactive magnetron sputtering with silver contents ranging from 4 to 8 at. %. The physical, chemical, structural, morphological/topographical, mechanical and tribological properties were evaluated. The tribological tests were performed in a unidirectional wear simulator, pin on disc, being the antagonists of a ceramic Al2O3 ball, and using simulate body fluids as lubricant. Hank’s Balanced Salt Solution (HBSS) and bovine serum albumin (BSA) in HBSS were chosen, in order to evaluate the lubrication ability of the solution containing the protein, albumin. The results revealed that the coatings with Ag content ranging from 4 to 8 at. %, were the most promising, as the tribological properties were superior to the results reported by other authors, which also developed Ag-TiCN coatings containing similar Ag contents and using similar test conditions. The presence of albumin lead to a lower wear in all the test conditions, and this enhancement was higher in the hydrophobic surfaces.This research is sponsored by FEDER funds through the program COMPETE - Programa Operacional Factores de Competitividade and by National funds through FCT - Fundacao para a Ciencia e a Tecnologia, in the framework of the Strategic Projects PEST-C/FIS/UI607/2011, and PEst-C/EME/UI0285/2011 and under the project, PTDC/CTM/102853/2008

    Proteasome-Mediated Regulation of Cdhr1a by Siah1 Modulates Photoreceptor Development and Survival in Zebrafish

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    Congenital retinal dystrophies are a major cause of unpreventable and incurable blindness worldwide. Mutations in CDHR1, a retina specific cadherin, are associated with cone-rod dystrophy. The ubiquitin proteasome system (UPS) is responsible for mediating orderly and precise targeting of protein degradation to maintain biological homeostasis and coordinate proper development, including retinal development. Recently, our lab uncovered that the seven in absentia (Siah) family of E3 ubiquitin ligases play a role in optic fissure fusion and identified Cdhr1a as a potential target of Siah. Using two-color whole mount in situ hybridization and immunohistochemistry, we detected siah1 and cdhr1a co-expression as well as protein localization in the retinal outer nuclear layer (ONL), and more precisely in the connecting cilium of rods and cones between 3–5 days post fertilization (dpf). We confirmed that Siah1 targets Cdhr1a for proteasomal degradation by co-transfection and co-immunoprecipitation in cell culture. To analyze the functional importance of this interaction, we created two transgenic zebrafish lines that express siah1 or an inactive siah1 (siah1ΔRING) under the control of the heat shock promoter to modulate Siah activity during photoreceptor development. Overexpression of siah1, but not siah1ΔRING, resulted in a decrease in the number of rods and cones at 72 h post fertilization (hpf). The number of retinal ganglion cells, amacrine and bipolar cells was not affected by Siah1 overexpression, and there was no significant reduction of proliferating cells in the Siah1 overexpressing retina. We did, however, detect increased cell death, confirmed by an increase in the number of TUNEL + cells in the ONL, which was proteasome-dependent, as proteasome inhibition rescued the cell death phenotype. Furthermore, reduction in rods and cones resulting from increased Siah1 expression was rescued by injection of cdhr1a mRNA, and to an even greater extent by injection of a Siah1-insensitive cdhr1a variant mRNA. Lastly, CRISPR induced loss of Cdhr1a function phenocopied Siah1 overexpression resulting in a significant reduction of rods and cones. Taken together, our work provides the first evidence that Cdhr1a plays a role during early photoreceptor development and that Cdhr1a is regulated by Siah1 via the UPS

    Natural polymorphisms of HIV type 2 pol sequences from drug-naive individuals

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    Until today, the susceptibility of human immunodeficiency virus type 2 (HIV-2) to protease and nucleosidic reverse-transcriptase inhibitors (PI and NRTI, respectively) has not been clearly documented. In this report we studied HIV-2 proviral sequences (n = 30) from drug-naive patients. Our results revealed that several amino acid positions in the protease and reverse transcriptase coding sequence harbored residues that have been associated with drug resistance in HIV-1-infected patients. In particular, the M46I substitution in the protease was detected in 90% of the sequences analyzed, which, together with the other substitutions identified, may indicate a reduced susceptibility of HIV-2-infected drug-naive patients to PI. Furthermore, interpretation of genotypic data with four available algorithms, developed for interpretation of HIV-1 sequence data, suggested nonoverlapping profiles of drug resistance

    Population structure of Pentaclethra macroloba (Willd.) Kuntze in high and low floodplains of the Amazonian estuary.

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    The flood cycle of floodplain forests and topographic variations are important factors of diversification and morphological and ecophysiological adaptations of the plant community. Pentaclethra macroloba is a hyperdominant species adapted to flood variations. The objective of this study was to characterize the P. macroloba population structure between environments with high topography, flooded only during the rainy season and peak flood of the river, (high várzea-HV) and low topography with daily flood (low várzea-LV). The study was carried in the Mazagão Experimental Field, Brazil. Four plots of 1 ha were installed in each environment. All individuals with DBH ≥ 5 cm were measured and georeferenced. ANOVA test, 0.05% probability, was applied to verify the structural differences between two environments. The HV had higher population density (51.2 individuals.ha-1) compared to the LV (36.7 individuals.ha-1), although without significance. Basal area was higher in the HV (10.42 m²) in comparison with LV (5.90 m²), with significant difference (F = 7.13, p = 0.00795). The maximum DAP of HV was 67 cm with mean of 24 cm. The LV presented maximum DBH of 42 cm with mean of 21 cm, showing structural difference between the two environments (F = 6.22, p = 0.0131). The aggregation index showed high aggregation in the LV (R = 0.89) than in the HV (R = 0.79), differing significantly between the two environments (F = 11.31, p = 0.0008). Frequency and time of flooding are ecological drives that structure the population of pracaxizeiro causing morphological and ecophysiological adaptations to the individual

    River damming affects seedling communities of a floodplain forest in the Central Amazon

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    The flood pulse of black water rivers in the Amazon basin determines the composition of species along the flood gradient in igapó forests. The Balbina dam, built on the Uatumã River, has altered the flood pulse and caused changes in the floristic composition of adult trees throughout the downstream area. There is a lack of studies on how communities of seedlings in igapó forests respond to changes in the flood pulse. This study investigates the response of seedling communities in the igapó forest downstream the Balbina dam and compares it with two pristine areas. The areas were sampled with transects of 1x25 m within 36 plots (25x25 m) along the flood gradient. Richness and dominance were calculated by simple regression and ordination analyses. The pristine areas had the same pattern of richness, dominance and genera distribution along the flood gradient. However, the affected Uatumã area formed different groups of genera by NMDS analysis, which divided them along the flood gradient with significantly increased dominance of three genera. The insertion of the Balbina dam resulted a loss of lateral and longitudinal connectivity for the Uatumã River, and the alteration to seedling communities may alter the future landscape of downstream igapó forests
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