998 research outputs found
Quality comparison of the HEVC and VP9 encoders performance
This paper reports a comparison between two recent video codecs, namely the HEVC and the VP9, using High Definition Video Sequences encoded with different bit rates. A subjective test for the evaluation of the provided Quality of Experience is reported. The video sequences were shown to a panel of subjects on a High Definition LED display and the subjective tests were performed using a Single Stimulus Methodology. The results shown that the HEVC encoder provides a better visual quality on low bit rates than the VP9. Similar performance was obtained for visually lossless conditions, although the HEVC requires lower bit rates to reach that level. Moreover, the correlation of the subjective evaluation and three tested objective metrics (PSNR, SSIM, and FSIM) revealed a good representation of the subjective results, particularly the SSIM and the FSIM metrics.info:eu-repo/semantics/publishedVersio
Socioterritorial movements. Cases from Latin America and Europe
Se desarrolla la noción de “movimientos socioterritoriales” del geógrafo Bernardo Mançano Fernandes, en tanto una categoría analítica específica para aquellos movimientos sociales que tienen como objetivo central la apropiación del espacio en pos de lograr su proyecto político.
Se distingue el concepto de movimiento socioterritorial del de movimiento social y del de movimiento socioespacial, y se proponen cuatro ejes: estrategia, identidad, sociabilidad política e instituciones, a través de tres casos de estudio: el MST en Brasil, la Organización Barrial Tupac Amaru en la Argentina y el movimiento “Occupy” en Londres. Se concluye con algunas diferencias claves entre los casos estudiados y se evalúan las potencialidades y límites del análisis socioterritorial.This paper develops Brazilian geographer Bernardo Mançano Fernandes’ notion of “socio-territorial movements” as an analytical category for social movements that have as their central objective the appropriation of space in pursuit of their political project. It does so by contrasting the concept of socio-territorial movement to those of social movement and sociospatial movement, and proposing four axes of analysis for socio-territorial movements: strategy, identity, political sociability and institutions. These axes are considered across three case studies: the MST in Brazil; an urban social movement from North-West Argentina called the “Tupac Amaru Neighborhood Organization”; and the 2011 “Occupy” movement in London. In conclusion, we discuss some key differences between the movements studied, and consider the limits to a socio-territorial analysis.Facultad de Humanidades y Ciencias de la Educació
Morphometrics of teropodomorph isolated teeth material from Bauru Basin (Upper Cretaceous, Southeast Brazil)
The theropod material of the Bauru Basin consists mainly of isolated teeth, bone elements being rare, generally isolated and fragmented. The best known theropod of the unity is Pycnonemosaurus nevesi, an abelisaurid described based on some fragmented elements. An ungeal phalanx, which possesses features found in derived maniraptorans, and a scapula associated with non-avialan mariraptorans have also been recovered from this basin. The rest of the bone material collected does not show diagnostic features. Regarding the isolated teeth, many studies have been conducted to increase the taxonomic knowledge of the Bauru theropods. These works, however, have fundamentally considered qualitative (or non-measurable) characters, like general shape or presence/absence of structures. Under these circumstances the material showed affinities to Abelisauroidea, Carcharodontosauridae and Maniraptora.
Nevertheless, the evaluation of dental characters from theropod dinosaurs in terms of taxonomic identification remains controversial. Although the methodology is considered relatively efficient concerning small theropods, its effectiveness on other theropod groups is questionable. The dental morphology can vary by position in the mouth and some characters considered as diagnostic, could be, in fact, shared among taxa. The present work aimed, based on a combination of measures of the teeth (crown length, base length and width, density of denticles and derived variables like, squatness and apex location with respect to base), to obtain taxonomic sorting of the isolated material, according to a quantitative methodology. By means of multivariate analysis it was possible to recognize statistically distinct groups. We used measures of teeth associated with cranial material already been published of a variety of theropod groups, to compare with our data. In some cases, similarities could be found, while other morphotypes were completely different. We believe that this methodology offer a more reliable tool to ascertain taxonomic relationships of Bauru Basin isolated teeth material. It's an attempt to make its fossil record more informative; its interpretation better founded, and perhaps standardized.Sesiones libresFacultad de Ciencias Naturales y Muse
The influence of root prominence on the onset of gingival recession: a systematic review
This systematic review aimed to identify, evaluate, and summarize the results of relevant studies on radicular prominence and its relationship with gingival recessions. This review was conducted according to the PRISMA (Preferred Reporting Reviews and Meta-Analysis) guidelines, and the focused PICO question was “In teeth with vestibular site-specific root or alveolar bone prominence, what are the chances that this will lead to gingival recession or difficulty in root coverage procedures, compared to teeth correctly positioned in the alveolar bone or without anatomical root prominence?”. A search was carried out on three databases: Embase, PubMed/MedLine, and Wiley Library. This initial search was complemented with manual research. It included any clinical study, such as a randomized clinical trial, controlled clinical trial, prospective/retrospective clinical study, case series, or case report, published in English from January 2012 to December 2023, which reported any involvement of the root/bone prominence approach. The exclusion criteria were clinical studies without report results/details of the case(s), studies based on questionnaires, editorial letters, any review, in vitro/in silica and animal studies, and interviews. The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement was applied for quality assessment. A total of 163 articles were found, but only three articles were included (k = 0.98). The included studies observed negative correlations when comparing the variables root prominence with linear root coverage, root surface area covered, and linear tissue thickness gain. It suggested a significant reduction in root coverage for prominences greater than 1 mm; therefore, relevant keratinized tissue gains can be achieved in gingival recession treatment after the application of the odontoplasty. The STROBE checklist evaluated 22 items, and all the included studies had a high-quality assessment (greater than 75%) with values greater than 85%. Then, it was not possible to draw conclusions due to the number of articles included, even though they had high-quality assessments. Otherwise, it is possible to suggest that the root prominence may impact gingival recession. Therefore, new and well-designed studies must be developed to establish a significant conclusion about this condition.info:eu-repo/semantics/publishedVersio
Identifying seawater intrusion in coastal areas by means of 1D and quasi-2D joint inversion of TDEM and VES data
Seawater intrusion is an increasingly widespread problem in coastal aquifers caused by climate changes –sea-level rise, extreme phenomena like flooding and droughts– and groundwater depletion near to the coastline. To evaluate and mitigate the environmental risks of this phenomenon it is necessary to characterize the coastal aquifer and the salt intrusion. Geophysical methods are the most appropriate tool to address these researches. Among all geophysical techniques, electrical methods are able to detect seawater intrusions due to the high resistivity contrast between saltwater, freshwater and geological layers. The combination of two or more geophysical methods is recommended and they are more efficient when both data are inverted jointly because the final model encompasses the physical properties measured for each methods. In this investigation, joint inversion of vertical electric and time domain soundings has been performed to examine seawater intrusion in an area within the Ferragudo-Albufeira aquifer system (Algarve, South of Portugal). For this purpose two profiles combining electrical resistivity tomography (ERT) and time domain electromagnetic (TDEM) methods were measured and the results were compared with the information obtained from exploration drilling. Three different inversions have been carried out: single inversion of the ERT and TDEM data, 1D joint inversion and quasi-2D joint inversion. Single inversion results identify seawater intrusion, although the sedimentary layers detected in exploration drilling were not well differentiated. The models obtained with 1D joint inversion improve the previous inversion due to better detection of sedimentary layer and the seawater intrusion appear to be better defined. Finally, the quasi-2D joint inversion reveals a more realistic shape of the seawater intrusion and it is able to distinguish more sedimentary layers recognised in the exploration drilling. This study demonstrates that the quasi-2D joint inversion improves the previous inversions methods making it a powerful tool applicable to different research areas.info:eu-repo/semantics/publishedVersio
Holographic representation: Hologram plane vs. object plane
Digital holography allows the recording, storage and subsequent reconstruction of both amplitude and phase of the light field scattered by an object. This is accomplished by recording interference patterns that preserve the properties of the original object field essential for 3D visualization, the so-called holograms.
Digital holography refers to the acquisition of holograms with a digital sensor, typically a CCD or a CMOS camera, and to the reconstruction of the 3D object field using numerical methods.
In the current work, the different representations of digital holographic information in the hologram and in the object planes are studied. The coding performance of the different complex field representations, notably Amplitude-Phase and Real-Imaginary, in both the hologram plane and the object plane, is assessed using both computer generated and experimental holograms. The HEVC intra main coding profile is used for the compression of the different representations in both planes, either for experimental holograms or computer generated holograms.
The HEVC intra compression in the object plane outperforms encoding in the hologram plane. Furthermore, encoding computer generated holograms in the object plane has a larger benefit than the same encoding over the experimental holograms. This difference was expected, since experimental holograms are affected by a larger negative influence of speckle noise, resulting in a loss of compression efficiency.
This work emphasizes the possibility of holographic coding on the object plane, instead of the common encoding in the hologram plane approach. Moreover, this possibility allows direct visualization of the Object Plane Amplitude in a regular 2D display without any transformation methods. The complementary phase information can easily be used to render 3D features such as depth map, multi-view or even holographic interference patterns for further 3D visualization depending on the display technology.info:eu-repo/semantics/publishedVersio
Electrical behaviour of the pump working as turbine in off grid operation
[EN] The use of pumps working as turbines (PATs) connected to the electric system, in the replacement of pressure reduction valves to reduce the excessive pressure in water distribution networks, have been studied for the last years. The introduction of PATs is very important in the water-energy nexus to promote the increase of the energy savings. As consequence, the majority of the water systems does not have access to the electrical grid and, therefore, the need to study the PATS operation off-grid is necessary. In this line, the novelty of this research is the application and optimization of a PAT in water systems when the recovery solution is off-grid type. To operate correctly, the induction machine requires an external source of reactive power, which is typically provided by the electrical grid. To supply the required reactive power, a bank of capacitors is installed at the machine terminals, so-called self-excited induction generator (SEIG). The analytical model, simulation and experimental works were performed, to analyse the SEIG behaviour. The results were applied in a SEIG-PAT system obtaining the global efficiency of the system for different speeds and loads. The global efficiency decreases 47% when off-grid operation, showing the need to optimize the electrical parameters of the generator to operate as off- grid with acceptable efficiency levels. In this framework, a tuning methodology for the SEIG capacitor bank values was developed to be automatically adjusted according to the operating point of the PAT to maximize its efficiency.This research is supported by Academic program career of the faculty of the Universitat Politecnica de Valencia 2016/2017 in the project "Maximization of the global efficiency in PATs in laboratory facility" and by FCT, through IDMEC, under LAETA, project UID/EMS/50022/2013. Besides, the authors wish to thank to the project REDAWN (Reducing Energy Dependency in Atlantic Area Water Networks) EAPA_198/2016 from INTERREG ATLANTIC AREA PROGRAMME 2014-2020 and CERIS (CEHIDRO-IST), the Hydraulic Laboratory, for the support in the conceptual work and in experiments on PATs.Capelo, B.; Pérez-Sánchez, M.; Fernandes, JFP.; Ramos, HM.; López Jiménez, PA.; Costa Branco, PJ. (2017). Electrical behaviour of the pump working as turbine in off grid operation. Applied Energy. 208:302-311. https://doi.org/10.1016/j.apenergy.2017.10.039S30231120
Polyphenol oxidase activity and colour changes of ‘Starking’ Apple cubes coated with alginate and dehydrated with air
The objective was to study the effect of alginate coating on polyphenol oxidase (PPO) activity and colour of ‘Starking’ apple cubes during dehydration with hot air. Apple cubes were dehydrated at 20°C, 35°C or 40°C, with a parallel air-flow. Analysis of PPO activity, colour (L*, a*, b*) and dry matter were performed along the dehydration process at each temperature. All samples presented a peak in relative PPO activity in the beginning of the drying. Exponential models fitted well the experimental data after the peak. Cubes without coating presented lower PPO activity, suggesting lower browning than coated samples throughout the dehydration process, for all temperatures. Better results for coated samples were obtained with a perpendicular airflow drying at 40°C, after dipping the whole apple in water at 60°C for 10 minutes. In order to prevent coated samples from browning, drying by perpendicular airflow preceded by a thermal treatment of the whole apple is required.info:eu-repo/semantics/publishedVersio
Evaluation of the adsorption potential of biochars prepared from forest and agri-food wastes for the removal of fluoxetine
Twelve biochars from forest and agri-food wastes (pruning of Quercus ilex, Eucalyptus grandis, Pinus pinaster, Quercus suber, Malus pumila, Prunus spinosa, Cydonia oblonga, Eriobotrya japonica, Juglans regia, Actinidia deliciosa, Citrus sinensis and Vitis vinifera) were investigated as potential low-cost and renewable adsorbents for removal of a commonly used pharmaceutical, fluoxetine. Preliminary adsorption experiments allowed to select the most promising adsorbents, Quercus ilex, Cydonia oblonga, Eucalyptus, Juglans regia and Vitis vinifera pruning material. They were characterized by proximate, elemental and mineral analysis, thermogravimetric analysis, Fourier transform infrared spectroscopy, determination of specific surface area and pH at the point of zero charge. Batch and equilibrium studies were performed, and the influence of pH was evaluated. The equilibrium was reached in less than 15 min in all systems. The maximum adsorption capacity obtained was 6.41 mg/g for the Eucalyptus biochar, which also demonstrated a good behavior in continuous mode (packed column).Manuela M. Moreira is grateful for the financial support financed by national funds through FCT – Fundação para a Ciência e a Tecnologia, I.P., within the scope of the project CEECIND/02702/2017 and to REQUIMTE/LAQV. The authors are also grateful for the financial support from FCT/MCTES through national funds (UID/QUI/50006/2019), project PTDC/ASP-PES/29547/2017 (POCI-01-0145-FEDER-29547) by FUNCAP and FCT/MCTES with national funds and co-funded by FEDER and to the projects “PTDC/BII-BIO/30884/2017” and WaterJPI/0007/2016 financed by ERA-NET Cofund Water Works 2015. The supply of the vineyard prunings is acknowledged to Sogrape, S.A. and the biochar production to Ibero Massa Florestal.info:eu-repo/semantics/publishedVersio
- …