| 1. |
- Ramos Do Prado, Samira B., et al.
(author)
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Physiological Degradation of Pectin in Papaya Cell Walls : Release of Long Chains Galacturonans Derived from Insoluble Fractions during Postharvest Fruit Ripening
- 2016
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In: Frontiers in Plant Science. - : Frontiers Media S.A.. - 1664-462X. ; 7
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Journal article (peer-reviewed)abstract
- Papaya (Carica papaya L.) is a fleshy fruit that presents a rapid pulp softening during ripening. However, the timeline on how papaya pectinases act in polysaccharide solubilization and the consequent modification of the cell wall fractions during ripening is still not clear. In this work, the gene expression correlations between, on one hand, 16 enzymes potentially acting during papaya cell wall disassembling and, on the other hand, the monosaccharide composition of cell wall fractions during papaya ripening were evaluated. In order to explain differences in the ripening of papaya samplings, the molecular mass distribution of polysaccharides from water-soluble and oxalate-soluble fractions (WSF and OSF, respectively), as well as the oligosaccharide profiling from the WSF fraction, were evaluated by high performance size exclusion chromatography coupled to a refractive index detector and high performance anion-exchange chromatography coupled to pulse amperometric detection analyses, respectively. Results showed that up-regulated polygalacturonase and β-galactosidase genes were positively correlated with some monosaccharide profiles. In addition, an overall increase in the retention time of high molecular weight (HMW) and low molecular weight (LMW) polysaccharides in WSF and OSF was shown. The apparent disappearance of one HMW peak of the OSF may result from the conversion of pectin that were crosslinked with calcium into more soluble forms through the action of PGs, which would increase the solubilization of polysaccharides by lowering their molecular weight. Thus, the results allowed us to propose a detailed process of papaya cell wall disassembling that would affect sensorial properties and post-harvesting losses of this commercially important fruit.
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| 2. |
- Araujo, Jefferson, et al.
(author)
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Characterizing complex mineral structures in thin sections of geological samples with a scanning hall effect microscope
- 2019
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In: Sensors. - : MDPI AG. - 1424-8220. ; 19:7
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Journal article (peer-reviewed)abstract
- We improved a magnetic scanning microscope for measuring the magnetic properties of minerals in thin sections of geological samples at submillimeter scales. The microscope is comprised of a 200 µm diameter Hall sensor that is located at a distance of 142 µm from the sample; an electromagnet capable of applying up to 500 mT DC magnetic fields to the sample over a 40 mm diameter region; a second Hall sensor arranged in a gradiometric configuration to cancel the background signal applied by the electromagnet and reduce the overall noise in the system; a custom-designed electronics system to bias the sensors and allow adjustments to the background signal cancelation; and a scanning XY stage with micrometer resolution. Our system achieves a spatial resolution of 200 µm with a noise at 6.0 Hz of 300 nT rms /(Hz) 1/2 in an unshielded environment. The magnetic moment sensitivity is 1.3 × 10 −11 Am 2 . We successfully measured the representative magnetization of a geological sample using an alternative model that takes the sample geometry into account and identified different micrometric characteristics in the sample slice.
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| 3. |
- Araujo, L. F., et al.
(author)
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In-fiber optofluidic alignment of Au-nanorods
- 2017
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In: Proceedings of SPIE - The International Society for Optical Engineering. - : SPIE. ; , s. 132-133
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Conference paper (peer-reviewed)abstract
- Optofluidic all-fiber devices are used for orientation of Au-nanorods under strongelectric fields. The dynamics is studied on sub-microsecond time-scales. A two-level laser rateequation model allows inferring diffusion rate, rotational mobility and other parameters.
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| 4. |
- Araujo, Leonardo F., et al.
(author)
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Photonics with special optical fibers and nanoparticles
- 2016
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In: Optics InfoBase Conference Papers. - 9781943580163
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Conference paper (peer-reviewed)abstract
- Optical properties of nanorods in the presence of external electric field when confined to a special optical fiber was investigated, showing an increase of the longitudinal absorption peak in the presence of the field.
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| 5. |
- Araújo, Marco, et al.
(author)
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A real options approach to decision making in broadband technology selection
- 2019
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In: International Journal of Multicriteria Decision Making. - 2040-106X .- 2040-1078. ; 8:2, s. 184-210
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Journal article (peer-reviewed)abstract
- The European Union has recently launched an ambitious plan to mitigate drastically, by 2025, the number of households lacking access to a 100 Mbps broadband connection through the subsidisation of the deployment of network infrastructure in rural areas. Decision makers such as governments and regulatory authorities therefore have to choose, among a pool of alternatives, a technology capable of delivering the required throughput on a large scale, based on a trade-off between the infrastructure costs and the subscribers’ perceived utility for each alternative. Such a trade-off is not simple, since there is no straightforward manner to rank the subscribers’ perceived utility against the network infrastructure cost. In this article, we propose a methodology based on real options, which outputs the value of each technology using multi-attribute value theory as an input, alongside the project’s risk and its costs.
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| 6. |
- Araújo, Marco, et al.
(author)
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A Utility Based Price Model for High Capacity Rural Networks in the European Union
- 2018
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In: 2018 IEEE 29th Annual International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC). - : IEEE. - 9781538660102 - 9781538660096 ; , s. 253-258
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Conference paper (peer-reviewed)abstract
- The European Union has been battling against the digital divide for several decades now when trying to mitigate the risk of social exclusion arising from the lack of broadband access, preventing citizens from full social and economic participation in the society. This has been done in the past by ensuring that a minimum set of services would be available to all end-users at an affordable price. However, various aspects of the rapid advances in technology, market developments and changes in user demand as well as the evolution of the telecommunications infrastructure (5G, IoT, Cloud, gigabit access, etc) increase the risk that citizens of rural areas are facing a severe risk of digital exclusion. To avoid this risk, the concept of subsidised rural networks was created by the European Commission. The idea as such is laudable, but the price tag remains unknown, which severely violates its implementability. In this article, based on the actual cost in a subsidised, but competitive, environment, we suggest a novel approach to realistically determine fair end-user's prices.
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| 7. |
- Araújo, Marco, et al.
(author)
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Risk assessment in 5G infrastructure deployment : an aid tool for estimating spectrum auction prices
- 2019
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In: 2019 IEEE Wireless Communications and Networking Conference Workshop (WCNCW). - : IEEE. - 9781728109237 - 9781728109220
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Conference paper (peer-reviewed)abstract
- Risks are significant when implementing large-scale projects such as 5G. The higher the overall risk of the 5G project, the lower the operators’ willingness to invest in millimetre wave spectrum and vice-versa; i.e. the price of the spectrum should be negatively correlated with the overall project risk. In this paper, we propose an array-based method for estimating financial risks when introducing 5G and its correspondence with spectrum prices. The method is based on Monte Carlo simulations, for deriving an appropriate maximum value for the operator’ willingness to pay for a 5G license.
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| 8. |
- Araújo, Marco, et al.
(author)
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Rural Networks Cost Comparison Between 5G (Mobile) and FTTx (Fixed) Scenarios
- 2018
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In: 2018 IEEE 29th Annual International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC). - : IEEE. - 9781538660102 - 9781538660096 ; , s. 259-264
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Conference paper (peer-reviewed)abstract
- In this article we simulate the infrastructure costs for very fast networks in rural areas. FTTH technology has been around for at least a decade, but two brand new technologies are expected to launch commercially in the next couple of years: 5G and G. Fast. This could have a strong impact on infrastructure costs and the fulfilment of the European Union, rural coverage objectives. 5G seems to be very promising since LTE is not a reasonable solution for very fast networks. FTTC has so far not been a valid alternative, since for the last mile, the only options for FTTC has been ADSL and VDSL, which however cannot reach very fast data rates. G.Fast is three times faster than VDSL and has the advantage, comparing to FTTH, that the last mile infrastructure is already build in the form of copper local loop.
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| 9. |
- Araújo, Marco, et al.
(author)
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Satellite backhaul for macro-cells, as an alternative to optical fibre, to close the digital divide
- 2019
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In: 2019 IEEE Wireless Communications and Networking Conference (WCNC). - : IEEE. - 9781538676479 - 9781538676462
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Conference paper (peer-reviewed)abstract
- The lack of broadband access causes a serious risk of social exclusion, by preventing citizens from full social and economic participation in the society. To avoid this risk, the concept of subsidized rural networks was developed by the European Commission, in which an operator builds, maintains and operates a network (usually an open network) capable of providing at least a 100 Mbps connection to the subscribers; deployed in low density regions being publicly subsidized when unprofitable. In this article, we suggest a methodology to measure a realistic value for the average broadband used per subscriber at busy hour. We also present a simulation model for the backhaul infrastructure costs for very fast networks in rural areas to cover the last, and more expensive, 5% of the population, while comparing optical fibre with satellite for the middle mile from an economical and financial perspective.
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| 10. |
- Bettencourt-Silva, Rita, et al.
(author)
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Diabetes-related symptoms, acute complications and management of diabetes mellitus of patients who are receiving palliative care : a protocol for a systematic review
- 2019
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In: BMJ Open. - : BMJ Publishing Group Ltd. - 2044-6055. ; 9:6
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Research review (peer-reviewed)abstract
- Introduction: Worldwide, an estimated 40 million people are in need of palliative care each year, but only 14% receive it. The incidence of diabetes mellitus (DM) in patients receiving palliative care is higher than in the general population. This association is intended to grow as a result of the rising burden of DM worldwide, ageing populations and the improved overall survival time of several diseases over the last few decades. Recommendations for DM management in the context of palliative care are mainly based on expert opinion as there is a lack of suitable evidence base and randomised clinical trials in palliative care are scarce. The aim of our systematic review is to identify the best DM management practices in order to reduce important DM-related symptoms and acute complications in patients receiving palliative care.Methods and analysis: The authors will study the DM treatment and management literature, surveying the different approaches employed to treat adult palliative patients. Core health bibliographic databases will be searched from January 1990 to May 2019. Data sources will include Ovid MEDLINE, Embase, PubMed, Web of Sciences, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, Scopus, Cumulative Index to Nursing and Allied Health Literature and grey literature. Details regarding diet, oral and injectable glucose-lowering medicines, insulin regimens and blood glucose monitoring strategies will he evaluated. We defined the primary outcomes to compare between DM management approaches as the presence of symptoms (polyuria, polydipsia and polyphagia) and acute complications of DM (hypoglycaemia, hyperglycaemic hyperosmolar state and diabetic ketoacidosis), and secondary outcomes as hospital admissions and deaths due to DM-related complications, health-related quality of life and glycaemic control.Ethics and dissemination: The systematic review methodology does not require ethics approval due to the nature of the study design. The results of the systematic review will be published in a peer-reviewed journal and will he publicly available.PROSPERO registration number: CRD42018115772.
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| 11. |
- da S. Ramos, Alessandro, et al.
(author)
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Comparative assessment between different sample preparation methodologies for PTGA CO2 adsorption assays—Pellet, powder, and fragment samples
- 2018
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In: Adsorption Science and Technology. - : Sage Publications. - 0263-6174 .- 2048-4038. ; 36:7-8, s. 1441-1455
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Journal article (peer-reviewed)abstract
- The carbon dioxide sorption process at coal seams is very important for understanding the trapping mechanisms of carbon capture and storage. The gas retention capacity of coal seams can be estimated using indirect methods based on the adsorption/desorption isotherms obtained in the laboratory. However, the gas sorption capacity can be overestimated or underestimated depending on the sample preparation. This work evaluates different sample preparations and their theoretical adsorption capacity using coal samples from the Cambui coal field (Parana Basin), southern Brazil. Experiments using a thermogravimetric balance were done to calculate the theoretical adsorption capacity, while sample characterization was done through immediate analysis, elementary analysis, and mineralogical studies. The sample preparations used in this work were powder, pellets, and fragments. While the powder form presents an average behavior, without any experimental complication, the pellet is extremely sensitive to any variation in the sample preparation, such as fractures, and the fragment requires a much longer experiment time than the other sample preparations, being impracticable for some cases.
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| 12. |
- Etcheverry, Sebastián, et al.
(author)
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Microsecond switching of plasmonic nanorods in an all-fiber optofluidic component
- 2017
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In: Optica. - : Optical Society of America. - 2334-2536. ; 4:8, s. 864-870
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Journal article (peer-reviewed)abstract
- As information technologies move from electron-to photon-based systems, the need to rapidly modulate light is of paramount importance. Here, we study the evolution of the electric-field-induced alignment of gold nanorods suspended in organic solvents. The experiments were performed using an all-fiber optofluidic device, which enables convenient interaction of light, electric fields, and the nanorod suspension. We demonstrate microsecond nanorod switching times, three orders of magnitude faster than a traditional Freederickcz-based liquid crystal alignment mechanism. We find that the dynamics of the alignment agrees well with the Einstein-Smoluchowski relationship, allowing for the determination of the rotational diffusion coefficient and polarizability anisotropy of the nanorods as well as the effective length of the ligands capping the nanorods. The ability to dynamically control the optical properties of these plasmonic suspensions coupled with the point-to-point delivery of light from the fiber component, as demonstrated in this work, may enable novel ultrafast optical switches, filters, displays, and spatial light modulators.
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| 13. |
- Pires, Ana Elisabete, et al.
(author)
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The curious case of the Mesolithic Iberian dogs : An archaeogenetic study
- 2019
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In: Journal of Archaeological Science. - : Elsevier BV. - 0305-4403 .- 1095-9238. ; 105, s. 116-129
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Journal article (peer-reviewed)abstract
- We investigated the genetic composition of six Canis remains from western Iberia, directly radiocarbon dated to 7,903-7,570 years (cal BP). They were identified as dogs via their archaeological and depositional context, osteometry, and a high percentage of aquatic diet shared with humans. For comparison, genetic data were obtained from an additional 37 Iberian dog remains from the Neolithic to Late Antiquity, as well as two Palaeolithic and a Chalcolithic Canis identified as wolves. Previous data indicated that dog mtDNA haplogroup A (HgA) is prevalent in extant European dogs ( > 50%), in the Near East and Asia, but rare or absent ( < 10%) in European Canis older than 3,000 years (cal BP). We found a high frequency (83%) of dog HgA in Mesolithic Iberian dog remains. This is the first report of a high frequency of dog HgA in pre-Neolithic Europe. We show that, contrary to the current view, Canis with HgA did not necessarily arrive in Europe from East-Asia. This phylogeographical difference in HgA frequency demonstrates that genetic differentiation was high prior to, or as a consequence of, domestication which may be linked with pre-Neolithic local processes for Iberian wolf domestication. Our results emphasize that knowledge of both ancient wolves' and early dogs' genetic profiles from the European periphery should improve our understanding of the evolution of the European dog.
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| 14. |
- Ramos, Alessandro da S., et al.
(author)
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Geochemical Characterization of Irati And Palermo Formations (Parana Basin-Southern Brazil) for Shale Oil/Gas Exploration
- 2015
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In: Energy Technology. - : Wiley-Blackwell. - 2194-4288. ; 3:5, s. 481-487
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Journal article (peer-reviewed)abstract
- Shale gas/oil currently are two of the most important unconventional energy resources. Their exploitation has caused an energy revolution in USA, and many countries are investing in it. Brazil has large areas covered with sedimentary basins, but little attention has been devoted to the study of shale containing oil and gas. The parameters analyzed and studied for geochemical data evaluation are: clay mineral identification, mineral matter analysis, elemental analysis (including total organic carbon, total carbon, H, N, and S), and the methane adsorption capacity of shale. Adsorption in Palermo Formation samples (depth 238.5m) was 13.72cm(3)g(-1) and for samples from Irati Formation (depth 218.45, 95.3, and 107.5m) 11.73, 6.17, and 4.61cm(3)g(-1).
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| 15. |
- Rodrigues, Gabriel S., et al.
(author)
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GoalD: A Goal-Driven Deployment Framework for Dynamic and Heterogeneous Computing Environments
- 2019
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In: Information and Software Technology. - : Elsevier BV. - 0950-5849. ; 111, s. 159-176
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Journal article (peer-reviewed)abstract
- Context Emerging paradigms like Internet of Things and Smart Cities utilize advanced sensing and communication infrastructures, where heterogeneity is an inherited feature. Applications targeting such environments require adaptability and context-sensitivity to uncertain availability and failures in resources and their ad-hoc networks. Such heterogeneity is often hard to predict, making the deployment process a challenging task. Objective This paper proposes GoalD as a goal-driven framework to support autonomous deployment of heterogeneous computational resources to fulfill requirements, seen as goals, and their correlated components on one hand, and the variability space of the hosting computing and sensing environment on the other hand. Method GoalD comprises an offline and an online stage to fulfill autonomous deployment by leveraging the use of goals. Deployment configuration strategies arise from the variability structure of the Contextual Goal Model as an underlying structure to guide autonomous planning by selecting available as well as suitable resources at runtime. Results We evaluate GoalD on an existing exemplar from the self-adaptive systems community – the Tele Assistance Service provided by Weyns and Calinescu [1]. Furthermore, we evaluate the scalability of GoalD on a repository consisting of 430,500 artifacts. The evaluation results demonstrate the usefulness and scalability of GoalD in planning the deployment of a system with thousands of components in a few milliseconds. Conclusion GoalD is a framework to systematically tackle autonomous deployment in highly heterogeneous computing environments, partially unknown at design-time following a goal-oriented approach to achieve the user goals in a target environment. GoalD has demonstrated itself able to scale for deployment planning dealing with thousands of components in a few milliseconds.
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| 16. |
- Rodrigues, Luiz F., et al.
(author)
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High-Pressure and Automatized System for Study of Natural Gas Hydrates
- 2019
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In: Energies. - : MDPI. - 1996-1073. ; 12:16
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Journal article (peer-reviewed)abstract
- Due to the declining of oil reserves in the world in the coming decades, gas hydrate (GH) is seen as the great promise to supply the planet's energy demand. With this, the importance of studying the behavior of GH, several researchers have been developing different systems that allow greater truthfulness in relation to the conditions where GH is found in nature. This work describes a new system to simulate formation (precipitation) and dissociation of GH primarily at natural conditions at deep-sea, lakes, and permafrost, but also applied for artificial gas hydrates studies (pipelines, and transport of hydrocarbons, CO2, and hydrogen). This system is fully automated and unique, allowing the simultaneous work in two independent reactors, built in Hastelloy C-22, with a capacity of 1 L and 10 L, facilitating rapid analyses when compared to higher-volume systems. The system can operate using different mixtures of gases (methane, ethane, propane, carbon dioxide, nitrogen, ammonia), high pressure (up to 200 bar) with high operating safety, temperature (-30 to 200 degrees C), pH controllers, stirring system, water and gas samplers, and hyphenated system with gas chromatograph (GC) to analyze the composition of the gases formed in the GH and was projected to possibility the visualizations of experiments (quartz windows).
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| 17. |
- Santos, Reginaldo, et al.
(author)
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Binder Identification Using Pattern Recognition on Phantom Measurements
- 2016
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In: IEEE Transactions on Instrumentation and Measurement. - 0018-9456. ; 65:3, s. 522-534
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Journal article (peer-reviewed)abstract
- This paper proposes an automatic method for the identification of twisted pairs (TPs) sharing the same binder, based on the analysis of phantom circuit measurements. This type of circuit is often used for improving data transmission rates in communication systems, but in this paper, phantoming is used to reveal if a four-wire loop composed of two TPs is close enough and well balanced in order to be considered in the same binder. The method uses four features extracted from scattering parameter measures in phantom-mode between two TPs. These features are related to the presence of periodicities and impedance mismatch between the measurement device and the four-wire transmission line. The identification is done via application of two pattern recognition techniques, support vector machines and K-means, on scattering parameter obtained from the phantom-mode measurement of two TPs. This paper also describes a method to determine the length of the two TPs that share the same binder. Laboratory results confirm the accuracy of the proposed methods.
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