| 1. |
- Abelev, Betty, et al.
(författare)
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Long-range angular correlations on the near and away side in p-Pb collisions at root S-NN=5.02 TeV
- 2013
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Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 719:1-3, s. 29-41
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Tidskriftsartikel (refereegranskat)abstract
- Angular correlations between charged trigger and associated particles are measured by the ALICE detector in p-Pb collisions at a nucleon-nucleon centre-of-mass energy of 5.02 TeV for transverse momentum ranges within 0.5 < P-T,P-assoc < P-T,P-trig < 4 GeV/c. The correlations are measured over two units of pseudorapidity and full azimuthal angle in different intervals of event multiplicity, and expressed as associated yield per trigger particle. Two long-range ridge-like structures, one on the near side and one on the away side, are observed when the per-trigger yield obtained in low-multiplicity events is subtracted from the one in high-multiplicity events. The excess on the near-side is qualitatively similar to that recently reported by the CMS Collaboration, while the excess on the away-side is reported for the first time. The two-ridge structure projected onto azimuthal angle is quantified with the second and third Fourier coefficients as well as by near-side and away-side yields and widths. The yields on the near side and on the away side are equal within the uncertainties for all studied event multiplicity and p(T) bins, and the widths show no significant evolution with event multiplicity or p(T). These findings suggest that the near-side ridge is accompanied by an essentially identical away-side ridge. (c) 2013 CERN. Published by Elsevier B.V. All rights reserved.
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| 2. |
- Abelev, Betty, et al.
(författare)
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Measurement of prompt J/psi and beauty hadron production cross sections at mid-rapidity in pp collisions at root s=7 TeV
- 2012
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Ingår i: Journal of High Energy Physics. - 1029-8479. ; :11
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Tidskriftsartikel (refereegranskat)abstract
- The ALICE experiment at the LHC has studied J/psi production at mid-rapidity in pp collisions at root s = 7 TeV through its electron pair decay on a data sample corresponding to an integrated luminosity L-int = 5.6 nb(-1). The fraction of J/psi from the decay of long-lived beauty hadrons was determined for J/psi candidates with transverse momentum p(t) > 1,3 GeV/c and rapidity vertical bar y vertical bar < 0.9. The cross section for prompt J/psi mesons, i.e. directly produced J/psi and prompt decays of heavier charmonium states such as the psi(2S) and chi(c) resonances, is sigma(prompt J/psi) (p(t) > 1.3 GeV/c, vertical bar y vertical bar < 0.9) = 8.3 +/- 0.8(stat.) +/- 1.1 (syst.)(-1.4)(+1.5) (syst. pol.) mu b. The cross section for the production of b-hadrons decaying to J/psi with p(t) > 1.3 GeV/c and vertical bar y vertical bar < 0.9 is a sigma(J/psi <- hB) (p(t) > 1.3 GeV/c, vertical bar y vertical bar < 0.9) = 1.46 +/- 0.38 (stat.)(-0.32)(+0.26) (syst.) mu b. The results are compared to QCD model predictions. The shape of the p(t) and y distributions of b-quarks predicted by perturbative QCD model calculations are used to extrapolate the measured cross section to derive the b (b) over bar pair total cross section and d sigma/dy at mid-rapidity.
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| 3. |
- Abelev, Betty, et al.
(författare)
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Underlying Event measurements in pp collisions at root s=0.9 and 7 TeV with the ALICE experiment at the LHC
- 2012
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Ingår i: Journal of High Energy Physics. - 1029-8479. ; :7
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Tidskriftsartikel (refereegranskat)abstract
- We present measurements of Underlying Event observables in pp collisions at root s = 0 : 9 and 7 TeV. The analysis is performed as a function of the highest charged-particle transverse momentum p(T),L-T in the event. Different regions are defined with respect to the azimuthal direction of the leading (highest transverse momentum) track: Toward, Transverse and Away. The Toward and Away regions collect the fragmentation products of the hardest partonic interaction. The Transverse region is expected to be most sensitive to the Underlying Event activity. The study is performed with charged particles above three different p(T) thresholds: 0.15, 0.5 and 1.0 GeV/c. In the Transverse region we observe an increase in the multiplicity of a factor 2-3 between the lower and higher collision energies, depending on the track p(T) threshold considered. Data are compared to PYTHIA 6.4, PYTHIA 8.1 and PHOJET. On average, all models considered underestimate the multiplicity and summed p(T) in the Transverse region by about 10-30%.
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| 4. |
- Algaba, Juan-Carlos, et al.
(författare)
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Broadband Multi-wavelength Properties of M87 during the 2017 Event Horizon Telescope Campaign
- 2021
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Ingår i: Astrophysical Journal Letters. - : American Astronomical Society. - 2041-8213 .- 2041-8205. ; 911:1
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Forskningsöversikt (refereegranskat)abstract
- In 2017, the Event Horizon Telescope (EHT) Collaboration succeeded in capturing the first direct image of the center of the M87 galaxy. The asymmetric ring morphology and size are consistent with theoretical expectations for a weakly accreting supermassive black hole of mass ∼6.5 × 109 M o˙. The EHTC also partnered with several international facilities in space and on the ground, to arrange an extensive, quasi-simultaneous multi-wavelength campaign. This Letter presents the results and analysis of this campaign, as well as the multi-wavelength data as a legacy data repository. We captured M87 in a historically low state, and the core flux dominates over HST-1 at high energies, making it possible to combine core flux constraints with the more spatially precise very long baseline interferometry data. We present the most complete simultaneous multi-wavelength spectrum of the active nucleus to date, and discuss the complexity and caveats of combining data from different spatial scales into one broadband spectrum. We apply two heuristic, isotropic leptonic single-zone models to provide insight into the basic source properties, but conclude that a structured jet is necessary to explain M87's spectrum. We can exclude that the simultaneous γ-ray emission is produced via inverse Compton emission in the same region producing the EHT mm-band emission, and further conclude that the γ-rays can only be produced in the inner jets (inward of HST-1) if there are strongly particle-dominated regions. Direct synchrotron emission from accelerated protons and secondaries cannot yet be excluded.
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| 5. |
- Brito, Haissa Oliveira, et al.
(författare)
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Immune-mediated febrile response in female rats: Role of central hypothalamic mediators
- 2020
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Ingår i: Scientific Reports. - : NATURE PUBLISHING GROUP. - 2045-2322. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- Lipopolysaccharide (LPS) induces fever through cytokines like receptor-activator of nuclear factor kappa B ligand (RANKL), triggering mediators like prostaglandins (PG), endothelin-1 (ET-1), corticotrophin-releasing factor (CRF), substance P (SP) and endogenous opioids. LPS-induced fever is reduced in females compared with males except in ovariectomized (OVX) females which show increased fever mediated by PG. The present study aimed to identify the mediators involved in fever in intact and OVX female rats. Fever was induced with LPS (50 mu g/kg) intraperitoneally or CRF (2.5 mu g), ET-1 (1 pg), morphine (10 mu g) and SP (500 ng) intracerebroventricularly in sham-operated and OVX rats. The role of RANKL was evaluated with osteoprotegerin (OPG, 1 mu g, intracerebroventricularly). Expression of RANK, CRFI/II, ETB, mu-opioid (MOR) and NK1 receptors was evaluated by confocal microscopy. Besides LPS, only morphine induced fever in OVX rats while all mediators induced fever in sham-operated animals. OPG abolished LPS-induced fever in OVX but not sham-operated animals. Overall, fever involves similar central mediators in cycling females and males but only morphine induced fever in OVX females. Importantly, RANK/RANKL participates in LPS-induced fever in OVX females, as in males but not in cycling females.
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| 6. |
- Frias Martinez, Maria Alejandra, et al.
(författare)
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Surface roughness of titanium disks influences the adhesion, proliferation and differentiation of osteogenic properties derived from human
- 2020
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Ingår i: International Journal of Implant Dentistry. - : Springer. - 2198-4034. ; 6:1
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Tidskriftsartikel (refereegranskat)abstract
- Purpose The aim of this study was to investigate the response of osteogenic cell lineage and gingival fibroblastic cells to different surface treatments of grade IV commercially pure Titanium (cpTi) disks. Material and methods Grade IV cpTi disks with different surfaces were produced: machined (M), sandblasting (B), sandblasting and acid subtraction (NP), and hydrophilic treatment (ACQ). Surface microtopography characteristics and chemical composition were investigated by scanning electron microscopy (SEM) and energy dispersive x-ray spectrometry (EDS). Adhesion and proliferation of SC-EHAD (human surgically-created early healing alveolar defects) and HGF-1 (human gingival fibroblasts) on Ti disks were investigated at 24 and 48 h, and osteogenic differentiation and mineralization were evaluated by assessing alkaline phosphatase (ALP) activity and alizarin red staining, respectively. Results No significant differences were found among the various surface treatments for all surface roughness parameters, except for skewness of the assessed profile (Rsk) favoring M (p= 0.035 ANOVA). M disks showed a slightly higher (p> 0.05; Kruskal-Wallis/Dunn) adhesion of HGF-1 (89.43 +/- 9.13%) than SC-EHAD cells (57.11 +/- 17.72%). ACQ showed a significantly higher percentage of SC-EHAD (100%) than HGF-1 (69.67 +/- 13.97%) cells adhered at 24 h. SC-EHAD cells expressed increased ALP activity in osteogenic medium at M (213%) and NP (235.04%) surfaces, but higher mineralization activity on ACQ (54.94 +/- 4.80%) at 14 days. Conclusion These findings suggest that surface treatment influences the chemical composition and the adhesion and differentiation of osteogenic cells in vitro.
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| 7. |
- Kattge, Jens, et al.
(författare)
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TRY plant trait database - enhanced coverage and open access
- 2020
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Ingår i: Global Change Biology. - : Wiley-Blackwell. - 1354-1013 .- 1365-2486. ; 26:1, s. 119-188
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Tidskriftsartikel (refereegranskat)abstract
- Plant traits-the morphological, anatomical, physiological, biochemical and phenological characteristics of plants-determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait-based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits-almost complete coverage for 'plant growth form'. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait-environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives.
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| 8. |
- Leblond, Claire S, et al.
(författare)
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Genetic and functional analyses of SHANK2 mutations suggest a multiple hit model of autism spectrum disorders.
- 2012
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Ingår i: PLoS Genetics. - : Public Library of Science (PLoS). - 1553-7390 .- 1553-7404. ; 8:2
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Tidskriftsartikel (refereegranskat)abstract
- Autism spectrum disorders (ASD) are a heterogeneous group of neurodevelopmental disorders with a complex inheritance pattern. While many rare variants in synaptic proteins have been identified in patients with ASD, little is known about their effects at the synapse and their interactions with other genetic variations. Here, following the discovery of two de novo SHANK2 deletions by the Autism Genome Project, we identified a novel 421 kb de novo SHANK2 deletion in a patient with autism. We then sequenced SHANK2 in 455 patients with ASD and 431 controls and integrated these results with those reported by Berkel et al. 2010 (n=396 patients and n=659 controls). We observed a significant enrichment of variants affecting conserved amino acids in 29 of 851 (3.4%) patients and in 16 of 1,090 (1.5%) controls (P=0.004, OR=2.37, 95% CI=1.23-4.70). In neuronal cell cultures, the variants identified in patients were associated with a reduced synaptic density at dendrites compared to the variants only detected in controls (P=0.0013). Interestingly, the three patients with de novo SHANK2 deletions also carried inherited CNVs at 15q11-q13 previously associated with neuropsychiatric disorders. In two cases, the nicotinic receptor CHRNA7 was duplicated and in one case the synaptic translation repressor CYFIP1 was deleted. These results strengthen the role of synaptic gene dysfunction in ASD but also highlight the presence of putative modifier genes, which is in keeping with the "multiple hit model" for ASD. A better knowledge of these genetic interactions will be necessary to understand the complex inheritance pattern of ASD.
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| 9. |
- Leborgne, Roberto Chouhy, et al.
(författare)
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New approach for power lines performance estimation based on load variation due to voltage sags
- 2011
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Ingår i: Electric power systems research. - : Elsevier BV. - 0378-7796 .- 1873-2046. ; 83:1, s. 35-40
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Tidskriftsartikel (refereegranskat)abstract
- The power line performance has traditionally been assessed in terms of its efficiency and reliability. The increase of the effect of voltage sags on sensitive loads, maybe located far away from the faulted line, is the reason to carry out a new analysis of power line's performance. A new method to evaluate the power line performance, based on voltage sag indices, is proposed. The voltage sag indices suggested to assess power lines performance are the load variation, the non delivered energy and the total cost due to voltage sags. The proposed power line performance is compared with the traditional performance based on power line outages. The results show that the proposed method can change the assessment of power lines performance and therefore the utility focus for investment.
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| 10. |
- Pereira-Gurgel, Virginia M., et al.
(författare)
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Abnormal vascular and neural retinal morphology in congenital lifetime isolated growth hormone deficiency
- 2016
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Ingår i: Growth Hormone and IGF Research. - : Elsevier BV. - 1096-6374 .- 1532-2238. ; 30-31, s. 11-15
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Tidskriftsartikel (refereegranskat)abstract
- © 2016 Elsevier LtdObjective Experimental models demonstrate an important role of GH in retinal development. However, the interactions between GH and the neuro-vascularization of the human retina are still not clear. A model of untreated congenital isolated GH deficiency (IGHD) may clarify the actions of GH on the retina. The purpose of this work was to assess the retinal neuro-vascularization in untreated congenital IGHD (cIGHD). Design In a cross sectional study, we performed an endocrine and ophthalmological assessment of 25 adult cIGHD subjects, homozygous for a null mutation (c.57+1G>A) in the GHRH receptor gene and 28 matched controls. Intraocular pressure measurement, retinography (to assess the number of retinal vascular branching points and the optic disc and cup size), and optical coherence tomography (to assess the thickness of macula) were performed. Results cIGHD subjects presented a more significant reduction of vascular branching points in comparison to controls (91% vs. 53% [p=0.049]). The percentage of moderate reduction was higher in cIGHD than in controls (p=0.01). The percentage of individuals with increased optic disc was higher in cIGHD subjects in comparison to controls (92.9% vs. 57.1%). The same occurred for cup size (92.9% vs. 66.7%), p<0.0001 in both cases. There was no difference in macula thickness. Conclusions Most cIGHD individuals present moderate reduction of vascular branching points, increase of optic disc and cup size, but have similar thickness of the macula.
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| 11. |
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| 12. |
- Antoniazzi, Igor, et al.
(författare)
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Oxygen intercalated graphene on SiC(0001) : Multiphase SiOx layer formation and its influence on graphene electronic properties
- 2020
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Ingår i: Carbon. - : Elsevier BV. - 0008-6223. ; 167, s. 746-759
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Tidskriftsartikel (refereegranskat)abstract
- Low-dimensionality materials are highly susceptible to interfaces. Indeed, intercalation of different chemical species in between epitaxial graphene and silicon carbide (SiC), for instance, may decouple the graphene with respect to the substrate due to the conversion of the buffer layer into a graphene layer. O-intercalation is known to release the strain of such 2D material and to lead to the formation of high structural quality AB-stacked bilayer graphene. Nonetheless, this interface transformation concomitantly degrades graphene electronic transport properties. In this work we employed different techniques in order to better understand the structure of the graphene/SiC interface generated by O-intercalation and to elucidate the origin of the poor electronic properties of graphene. Experimental results revealed the formation of a SiO2 rich layer with a defective transition layer in between it and the SiC, which is characterized by the existence of silicon oxycarbide structures. Scanning tunneling spectroscopy measurements revealed an extensive presence of electronic states just around the Fermi level all over the sample surface, which may suppress the charge carriers mobility around this region. According to theoretical calculations, such states are mainly due to the formation of silicon oxicarbides within the interfacial layer.
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| 13. |
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| 14. |
- Barbieri, Dechristian, et al.
(författare)
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Sit-stand tables with semi-automated position changes : a new interactive approach for reducing sitting in office work
- 2017
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Ingår i: IISE Transactions on Occupational Ergonomics and Human Factors. - : Informa UK Limited. - 2472-5838 .- 2472-5846. ; 5:1, s. 39-46
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Tidskriftsartikel (refereegranskat)abstract
- Background: Introduction of sit-stand tables has been proposed as an initiative to decrease sedentary behavior among office workers and thus reduce risks of negative cardiometabolic health effects. However, ensuring proper and sustainable use of such tables has remained a challenge for successful implementation. Objective: We developed a new system to promote and sustain the use of sit-stand tables. Methods: The system was programmed to change the position of the table between “sit” and “stand” positions according to a regular pre-set pattern, if the user agreed to the system-generated prompts prior to each change. The user could respond to the system-generated prompts by agreeing, refusing or delaying the changes by 2 minutes. We obtained user compliance data when this system was programmed to a schedule of 10 minutes of standing after every 50 minutes of sitting. Compliance was investigated in nine office workers who were offered the semi-automated sit-stand table for two months. Results: On average, the system issued 12-14 alerts per day throughout the period. Average acceptance rate ranged from 75.0-82.4%, and refusal rate ranged from 11.8-10.1% between the first and eighth weeks of intervention (difference not statistically significant). During the first week after introduction, the table was in a standing position for 75.2 min on average, increasing slightly to 77.5 min in the eighth week. Conclusion: Since the workers were essentially sitting down before the table was introduced, these results suggest that the system was accepted well, and led to an effective reduction of sitting during working hours. Users also reported that the system contributed positively to their health and wellbeing, without interrupt their regular work, and that they would like to continue using the sit-stand table even beyond the two-month period, as part of their regular work. Compliance beyond two months of use, however, needs to be verified.
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| 15. |
- Beal, Jacob, et al.
(författare)
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Robust estimation of bacterial cell count from optical density
- 2020
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Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
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| 16. |
- Bernal, Ximena E., et al.
(författare)
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Empowering Latina scientists
- 2019
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 363:6429, s. 825-826
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 17. |
- Boeira, Rafael, et al.
(författare)
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Propagation of Voltage Dips in a Mixed DFIG-PMSG Wind Power Plant
- 2021
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Ingår i: 2021 IEEE PES Innovative Smart Grid Technologies Conference - Latin America (ISGT Latin America). - : IEEE.
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Konferensbidrag (refereegranskat)abstract
- This work assesses the propagation of voltage dips caused by electrical faults in a mixed DFIG-PMSG wind power plant by considering distinct collection transformer connections. Several transmission system operators have required the operation of the wind power plants even during voltage dips. The electronic converters might be affected during the voltage dips. Most of the works which assess this impact applied voltage dips directly to wind turbine terminals. However, the voltage dips which reach the wind turbine terminals are distinct in type of the ones from the transmission level. The reason for this distinction is related to the winding connections of the wind turbines and collection grid transformers. The winding connection of the collection grid varies country by country, i.e some countries apply Yg- Yg and other Yg - A. Faced with this, the consideration of the winding connections might possibly lead to distinct operation of the wind turbines during the voltage dip. Besides, the operation during dips also differs depending on the converter technology. This way, this works aims to analyze how the low-voltage ride-through requirements and the behavior of the wind turbines changes in terms of the collection grid transformer for two technologies of wind turbines: PMSG and DFIG.
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| 18. |
- Bonfanti, A., et al.
(författare)
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TOI-1055 b: Neptunian planet characterised with HARPS, TESS, and CHEOPS
- 2023
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 671
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Tidskriftsartikel (refereegranskat)abstract
- Context. TOI-1055 is a Sun-like star known to host a transiting Neptune-sized planet on a 17.5-day orbit (TOI-1055 b). Radial velocity (RV) analyses carried out by two independent groups using nearly the same set of HARPS spectra have provided measurements of planetary masses that differ by ∼2σ. Aims. Our aim in this work is to solve the inconsistency in the published planetary masses by significantly extending the set of HARPS RV measurements and employing a new analysis tool that is able to account and correct for stellar activity. Our further aim was to improve the precision on measurements of the planetary radius by observing two transits of the planet with the CHEOPS space telescope. Methods. We fit a skew normal function to each cross correlation function extracted from the HARPS spectra to obtain RV measurements and hyperparameters to be used for the detrending. We evaluated the correlation changes of the hyperparameters along the RV time series using the breakpoint technique. We performed a joint photometric and RV analysis using a Markov chain Monte Carlo scheme to simultaneously detrend the light curves and the RV time series. Results. We firmly detected the Keplerian signal of TOI-1055 b, deriving a planetary mass of Mb = 20.4-2.5+2.6 MO (∼12%). This value is in agreement with one of the two estimates in the literature, but it is significantly more precise. Thanks to the TESS transit light curves combined with exquisite CHEOPS photometry, we also derived a planetary radius of Rb = 3.490-0.064+0.070 RO (∼1.9%). Our mass and radius measurements imply a mean density of ρb = 2.65-0.35+0.37 g cm-3 (∼14%). We further inferred the planetary structure and found that TOI-1055 b is very likely to host a substantial gas envelope with a mass of 0.41-0.20+0.34 MO and a thickness of 1.05-0.29+0.30 RO. Conclusions. Our RV extraction combined with the breakpoint technique has played a key role in the optimal removal of stellar activity from the HARPS time series, enabling us to solve the tension in the planetary mass values published so far for TOI-1055 b.
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| 19. |
- Castro Alves, Victor, 1986-, et al.
(författare)
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Size matters : TLR4-mediated effects of α-(1,5)-linear arabino-oligosaccharides in macrophage-like cells depend on their degree of polymerization
- 2021
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Ingår i: Food Research International. - : Elsevier. - 0963-9969 .- 1873-7145. ; 141
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Tidskriftsartikel (refereegranskat)abstract
- Linear arabino-oligosaccharides (LAOS) produced from controlled enzymatic hydrolysis of arabinans from sugar beet are well-known because of their chain-length dependent prebiotic effects. However, it is not clear if these α-(1,5)-linked arabinose oligosaccharides can interact directly with immune system cells, as well as if its degree of polymerization (DP) influences possible biological effects. Four high purity LAOS with distinct DP were tested in macrophage-like cells exposed or not to LPS. Results shown that LAOS interact with Toll-like receptor (TLR) 4 in a chain length-dependent manner. LAOS with higher DP induce stimulatory effects mainly through the TLR4/MyD88 pathway, thereby enhancing the release of tumor necrosis factor alpha (TNF-α), interleukin (IL-) 1β, 6, 12, and chemokines including MCP-1, RANTES, IL-8, and IP-10. Notably, LAOS with lower DP appears to have an opposite effect to those counterparts with higher DP, as they does not induce the secretion of cytokines and chemokines in macrophages-like cells, while also inhibit TLR4-mediated effects induced by both lipopolysaccharide and LAOS with higher DP. These findings provide not only insights into potential biological effects of LAOS, but also reveal that controlled enzymatic hydrolysis of sugar beet arabinans may lead to dietary oligosaccharides with desired biological properties.
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| 20. |
- Clé de Oliveira, Thiago, et al.
(författare)
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Voltage Sags: Statistical Evaluation of Monitoring Results based on Predicted Stochastic Simulation
- 2006
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Ingår i: 12th International Conference on Harmonics and Quality of Power.
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Konferensbidrag (refereegranskat)abstract
- This paper presents a methodology specially developed for the estimation of voltage sag characteristics such as magnitude and frequency. The aim of this methodology is to evaluate sags monitoring results based on a stochastic assessment of long-term voltage sag indices. The measured sag indices are evaluated by means of two statistic tools, namely the confidence interval and analysis of variance based on hypothesis testing. A case study based on the evaluation of a six-month monitoring period shows the applicability of the proposed methodology.
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| 21. |
- de Oliveira, Maria I. A., et al.
(författare)
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Optical properties of organosilicon compounds containing sigma-electron delocalization by quasiparticle self-consistent GW calculations
- 2021
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Ingår i: Spectrochimica Acta Part A - Molecular and Biomolecular Spectroscopy. - : Pergamon Press. - 1386-1425 .- 1873-3557. ; 245
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Tidskriftsartikel (refereegranskat)abstract
- We investigate theoretically the electronic and optical absorption properties of two sub-classes of oligosilanes: (i) Si(CH3)(4), Si-4(CH3)(8), and Si-8(CH3)(8) that contain Si dot, ring and cage, respectively, and exhibit typical Si-C and Si-Si bonds; and (ii) persilastaffanes Si7H6(CH3)(6) and Si12H6(CH3)(12), which contain extended delocalized s-electrons in Si-Si bonds over three-dimensional Si frameworks. Our modeling is performed within the GW approach up to the partially self-consistent GW(0) approximation, which is more adequate for reliably predicting the optical band gaps of materials. We examine how the optical properties of these organosilicon compounds depend on their size, geometric features, and Si/C composition. Our results indicate that the present methodology offers a viable way of describing the optical excitations of tailored functional Si-C-based clusters and molecular optical tags with potential use as efficient light absorbers/emitters in molecular optical devices. (C) 2020 The Author(s). Published by Elsevier B.V.
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| 22. |
- de Oliveira, Roger Alves, et al.
(författare)
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Comparative Analysis of Transformer-Energizing and Fault-Caused Voltage Dips on the Dynamic Behavior of DFIG-Based Wind Turbines
- 2020
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Ingår i: Proceedings of 2020 IEEE PES Innovative Smart Grid Technologies Europe (ISGT-Europe) 26-28 October, 2020. - : IEEE. ; , s. 589-593
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Konferensbidrag (refereegranskat)abstract
- This work compares the response of DFIG-based wind turbines under voltage dips caused by transformer-energizing and caused by an asymmetrical fault. Voltage dips with similar retained voltage and duration and the two distinct causes are applied to an equivalent model of a DFIG-based wind park. The dips are different in terms of harmonic content and unbalance during the recovery after the dip. Due to its slow recovery, the transformer-energizing dip results in longer fluctuation in torque, longer overshoot in DC-link voltage, and longer recovery to the pre-dip active power. Also, due to its harmonic content, the harmonic distortion in the rotor and stator current is higher for the transformer-energizing dip. As the impact is different between the transformer-energizing dip and the fault-caused dip, it is recommended to consider both events separately during low-voltage-ride-through studies.
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| 23. |
- de Oliveira, Roger Alves, et al.
(författare)
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Evaluation of the DFIG-based Wind Turbine Subjected to Transformer-energizing Voltage Dips
- 2019
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Ingår i: NORPIE 2019 - Nordic Workshop on Power and Industrial Electronics, Conference Proceeding. - : Institute of Electrical and Electronics Engineers (IEEE).
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Konferensbidrag (refereegranskat)abstract
- This work evaluates the response of DFIG-based wind turbine under voltage dips caused by transformer energizing. The transformer energizing is part of the normal operation of the power system and it can cause even-harmonic distortion, which could impact the operation of the power converters on the wind turbine. Previous works only considered voltage dips caused by electrical faults, then other causes should be understood to guarantee sufficient fault-right through of wind power installations. In order to address this study, voltage dips measurements with distinct magnitude, harmonic distortion and voltage unbalance are applied to a DFIG model. The impacts on the rotor current, on the DC-link voltage, and on the DFIG active power are analyzed.
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- de Oliveira, Roger Alves, et al.
(författare)
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Short-Term Distortion and Protection Operation in DFIG-Based Wind Parks during Voltage Dips
- 2020
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Ingår i: Proceedings of 2020 IEEE PES Innovative Smart Grid Technologies Europe (ISGT-Europe) 26-28 October, 2020. - : IEEE. ; , s. 819-823
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Konferensbidrag (refereegranskat)abstract
- Due to the increasing penetration of wind power, grid codes require that the wind farms remain connected to the grid during voltage dips. The harmonic distortion might change during the short-term reduction in the voltage magnitude. Although the distortion only occurs during the short period of the voltage dip, high levels of harmonic might cause mal-operation of the protective devices in a wind power plant. The main negative influence that harmonics can have on wind power plant protection is that it can act unnecessarily. This work analysis the changes in the harmonic content in the voltages and currents during dips in a DFIG-based wind power plant. The results showed that the total harmonic distortion for the voltages in the collector system and at the terminals of the wind turbines increases during asymmetrical dips. The currents were affected for both symmetrical and asymmetrical dips. The third and seventh harmonics were the voltage components that most increased. For the currents, the increase was in the third harmonic and interharmonics.
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