159 research outputs found

    An Exploratory Empirical Assessment of Italian Open Government Data Quality With an eye to enabling linked open data

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    Context The diffusion of Linked Data and Open Data in recent years kept a very fast pace. However evidence from practitioners shows that disclosing data without proper quality control may jeopardize datasets reuse in terms of apps, linking, and other transformations. Objective Our goals are to understand practical problems experienced by open data users in using and integrating them and build a set of concrete metrics to assess the quality of disclosed data and better support the transition towards linked open data. Method We focus on Open Government Data (OGD), collecting problems experienced by developers and mapping them to a data quality model available in literature. Then we derived a set of metrics and applied them to evaluate a few samples of Italian OGD. Result We present empirical evidence concerning the common quality problems experienced by open data users when using and integrating datasets. The measurements effort showed a few acquired good practices and common weaknesses, and a set of discriminant factors among datasets. Conclusion The study represents the first empirical attempt to evaluate the quality of open datasets at an operational level. Our long-term goal is to support the transition towards Linked Open Government Data (LOGD) with a quality improvement process in the wake of the current practices in Software Qualit

    Thermal storage of nitrate salts as Phase Change Materials (PCMs)

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    This study presents the energy storage potential of nitrate salts for specific applications in energy systems that use renewable resources. For this, the thermal, chemical, and morphological characterization of 11 samples of nitrate salts as phase change materials (PCM) was conducted. Specifically, sodium nitrate (NaNO3), sodium nitrite (NaNO2), and potassium nitrate (KNO3) were considered as base materials; and various binary and ternary mixtures were evaluated. For the evaluation of the materials, differential Fourier transform infrared spectroscopy (FTIR), scanning calorimetry (DSC), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM) to identify the temperature and enthalpy of phase change, thermal stability, microstructure, and the identification of functional groups were applied. Among the relevant results, sodium nitrite presented the highest phase change enthalpy of 220.7 J/g, and the mixture of 50% NaNO3 and 50% NaNO2 presented an enthalpy of 185.6 J/g with a phase change start and end temperature of 228.4 and 238.6 °C, respectively. This result indicates that sodium nitrite mixtures allow the thermal storage capacity of PCMs to increase. In conclusion, these materials are suitable for medium and high-temperature thermal energy storage systems due to their thermal and chemical stability, and high thermal storage capacity

    Introducción al Análisis e Implementación de Sistemas de Control Automático

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    Introducción al Análisis e implementación de Sistemas de Control Automático es un libro de texto para estudiantes universitarios y profesionales interesados en el estudio de los conceptos básicos de la teoría de control en el dominio del tiempo y de la frecuencia con aplicaciones en el diseño clásico y moderno de los sistemas de control automático. En esta primera edición, en sus dos primeros capítulos tratan sobre los fundamentos de los sistemas de control y el modelamiento de los sistemas eléctrico, mecánicos y electromecánicos

    Plankton rotifers from a tropical lake: differences in distribution and migration patterns in two mixing events, with similar abiotic conditions.

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    Vertical distribution of plankton rotifers is not random. Although the causes of this behavior are still under debate, it has been suggested, mainly from the study of stratified environments, that abiotic parameters play an important role in determining the presence and position of a species in the water column. We compared the composition and vertical distribution of planktonic rotifers in a tropical monomictic lake in Mexico during the mixing period of two years in which abiotic conditions were similar. We recorded 28 rotifer species. Total average densities ranged from 238±39 ind l-1 to 517±97 ind l-1. The similarity of rotifer assemblages between the two compared dates was 46.4%. Our results showed that temperature and dissolved oxygen in the upper 13 meters and pH upper 8 meters, respectively, were homogeneous in the two dates. Nevertheless, the rotifer assemblages showed important differences in: a) the absolute population densities, b) the dominance ranking of species in the community, c) the preferential position of a specific species in the water column, d) the relationship between such preference and the studied abiotic factors and, e) the types and amplitudes of species migrations. Given the resemblance of the abiotic factors in the analyzed years, we suggest that changes in rotifers distribution and abundance would involve biological factors, such as food availability, competition and predation.

    Optimal Nitrogen Fertilization to Reach the Maximum Grain and Stover Yields of Maize (Zea mays L.): Tendency Modeling

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    Utilization of maize stover to the production of meat and milk and saving the grains for human consumption would be one strategy for the optimal usage of resources. Variance and tendency analyses were applied to find the optimal nitrogen (N) fertilization dose (0, 100, 145, 190, 240, and 290 kg/ha) for forage (F), stover (S), cob (C), and grain (G) yields, as well as the optimal grain-to-forage, cob-to-forage, and cob-to-stover ratios (G:F, C:F, and C:S, respectively). The study was performed in central Mexico (20.691389° N and −101.259722° W, 1740 m a.m.s.l.; Cwa (Köppen), 699 mm annual precipitation; alluvial soils). N-190 and N-240 improved the individual yields and ratios the most. Linear and quadratic models for CDM, GDM, and G:F ratio had coefficients of determination (R2) of 0.20–0.46 (p < 0.03). Cubic showed R2 = 0.30–0.72 (p < 0.02), and the best models were for CDM, GDM, and the G:F, C:F, and C:S DM ratios (R2 = 0.60–0.72; p < 0.0002). Neither SHB nor SDM negatively correlated with CDM or GDM (r = 0.23–0.48; p < 0.0001). Excess of N had negative effects on forage, stover, cobs, and grains yields, but optimal N fertilization increased the proportion of the G:F, C:F, and C:S ratios, as well as the SHB and SDM yields, without negative effects on grain production

    Temperature-induced melting of double-stranded DNA in the absence and presence of covalently bonded antitumour drugs: insight from molecular dynamics simulations

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    The difference in melting temperature of a double-stranded (ds) DNA molecule in the absence and presence of bound ligands can provide experimental information about the stabilization brought about by ligand binding. By simulating the dynamic behaviour of a duplex of sequence 5′-d(TAATAACGGATTATT)·5′-d(AATAATCCGTTATTA) in 0.1 M NaCl aqueous solution at 400 K, we have characterized in atomic detail its complete thermal denaturation profile in <200 ns. A striking asymmetry was observed on both sides of the central CGG triplet and the strand separation process was shown to be strongly affected by bonding in the minor groove of the prototypical interstrand crosslinker mitomycin C or the monofunctional tetrahydroisoquinolines trabectedin (Yondelis®), Zalypsis® and PM01183®. Progressive helix unzipping was clearly interspersed with some reannealing events, which were most noticeable in the oligonucleotides containing the monoadducts, which maintained an average of 6 bp in the central region at the end of the simulations. These significant differences attest to the demonstrated ability of these drugs to stabilize dsDNA, stall replication and transcription forks, and recruit DNA repair proteins. This stabilization, quantified here in terms of undisrupted base pairs, supports the view that these monoadducts can functionally mimic a DNA interstrand crosslink

    Natural CD4+ T-Cell Responses against Indoleamine 2,3-Dioxygenase

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    The enzyme indoleamine 2,3-dioxygenase (IDO) contributes to immune tolerance in a variety of settings. In cancer IDO is expressed within the tumor itself as well as in antigen-presenting cells in tumor-draining lymph nodes, where it endorses the establishment of peripheral immune tolerance to tumor antigens. Recently, we described cytotoxic CD8(+) T-cell reactivity towards IDO-derived peptides.In the present study, we show that CD4(+) helper T cells additionally spontaneously recognize IDO. Hence, we scrutinized the vicinity of the previously described HLA-A*0201-restricted IDO-epitope for CD4(+) T-cell epitopes. We demonstrated the presence of naturally occurring IDO-specific CD4(+) T cells in cancer patients and to a lesser extent in healthy donors by cytokine release ELISPOT. IDO-reactive CD4(+) T cells released IFN-γ, TNF-α, as well as IL-17. We confirm HLA class II-restriction by the addition of HLA class II specific blocking antibodies. In addition, we detected a trend between class I- and class II-restricted IDO responses and detected an association between IDO-specific CD4(+) T cells and CD8(+) CMV-responses. Finally, we could detect IL-10 releasing IDO-reactive CD4(+) T cells.IDO is spontaneously recognized by HLA class II-restricted, CD4(+) T cells in cancer patients and in healthy individuals. IDO-specific T cells may participate in immune-regulatory networks where the activation of pro-inflammatory IDO-specific CD4(+) responses may well overcome or delay the immune suppressive actions of the IDO-protein, which are otherwise a consequence of the early expression of IDO in maturing antigen presenting cells. In contrast, IDO-specific regulatory T cells may enhance IDO-mediated immune suppression

    Increased Systemic Th17 Cytokines Are Associated with Diastolic Dysfunction in Children and Adolescents with Diabetic Ketoacidosis

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    Diastolic dysfunction suggestive of diabetic cardiomyopathy is established in children with T1DM, but its pathogenesis is not well understood. We studied the relationships of systemic inflammatory cytokines/chemokines and cardiac function in 17 children with T1DM during and after correction of diabetic ketoacidosis (DKA). Twenty seven of the 39 measured cytokines/chemokines were elevated at 6–12 hours into treatment of DKA compared to values after DKA resolution. Eight patients displayed at least one parameter of diastolic abnormality (DA) during acute DKA. Significant associations were present between nine of the cytokine/chemokine levels and the DA over time. Interestingly, four of these nine interactive cytokines (GM-CSF, G-CSF, IL-12p40, IL-17) are associated with a Th17 mediated cell response. Both the DA and CCL7 and IL-12p40, had independent associations with African American patients. Thus, we report occurrence of a systemic inflammatory response and the presence of cardiac diastolic dysfunction in a subset of young T1DM patients during acute DKA

    Developments and applications of the OPTIMADE API for materials discovery, design, and data exchange

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    The Open Databases Integration for Materials Design (OPTIMADE) application programming interface (API) empowers users with holistic access to a growing federation of databases, enhancing the accessibility and discoverability of materials and chemical data. Since the first release of the OPTIMADE specification (v1.0), the API has undergone significant development, leading to the upcoming v1.2 release, and has underpinned multiple scientific studies. In this work, we highlight the latest features of the API format, accompanying software tools, and provide an update on the implementation of OPTIMADE in contributing materials databases. We end by providing several use cases that demonstrate the utility of the OPTIMADE API in materials research that continue to drive its ongoing development
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