The introduction of real numbers in secondary education. An institutional analysis of textbooks

In this paper we analyse the introduction of irrational and real numbers in secondary textbooks, and specifically the propositions on how these should be taught, in a sample of Brazilian textbooks used in state schools and approved by the Ministry of Education. The analyses discussed in this paper follow an institutional perspective (using Chevallard's Anthropological Theory of Didactics). Our results indicate that the notion of irrational number is generally introduced on the basis of the decimal representation of numbers, and that the mathematical need for the construction of the field of real numbers remains unclear in the textbooks. It seems that textbooks used in secondary teaching institutions develop mathematical organisations which focus on the practical block

Contribution of GIS and Geochemical Proxies to Improving Habitat Identification and Delimitation for the Natura 2000 Network: The Case of Coastal Lagoons in Galicia (NW Iberian Peninsula)

The Natura 2000 network is an ambitious European project aimed at nature conservation. Nevertheless, the identification and delimitation of habitats is a complex task and simultaneously essential for correct ecosystem management. In this study we compared the current habitat delimitation and designation and the results produced by Geographic Information Systems (GIS) and geochemical proxies for the categorization of four coastal lakes in Galicia (NW Iberian Peninsula). The findings reveal important errors in the delimitation/designation. The first error is the designation of all four lakes as Coastal lagoons (habitat 1150), when geochemical data indicate that two of these lakes were always freshwater lakes and should consequently be classified as Natural eutrophic lakes (habitat 3150). Another error is of conceptual origin, because the lakes comprise a unique functional system composing of different environmental units (e.g., open water or aquatic vegetation). Subdivision into different habitats is therefore meaningless for units of negligible surface area. In addition, the designation of some habitats is very dubious according to the available data. Finally, notable changes in relation to the temporal changes of wetlands were observed. Thus, the area occupied by aquatic macrophytes increased greatly at the expense of open waters, and the increase was also reflected in the alluvial forest. This last finding indicates the importance of updating the state of Natura 2000 network in Galicia to improve habitat managementThis work is part of a research project entitled “Monitorización de los procesos biogeoquímicos en las lagunas litorales en relación con su calidad ambiental y respuesta al cambio climático” (Xunta de Galicia, PGIDIT08MDS036000PR), the program for consolidation of competitive research groups (Axudas á consolidación e estruturación de unidades de investigación competitivas do SUG del Plan Galego IDT, Ambiosol Group ref. 2018-PG036), and Cross-Research in Environmental Technologies, CRETUS (Xunta de Galicia GRUP2015/02, ref. 2018-PG100). A.G.-P. is supported by an FPU predoctoral contract by the Spanish government (Ministerio de Educación, Cultura y Deporte). Grant Number: FPU16/03050S

A política monetária não convencional na crise recente : uma análise dos fundamentos teóricos e do policymaking no período

Expõe o que consiste, tanto em teoria quanto na prática, a recente onda de medidas extraordinárias adotadas pelos bancos centrais ao redor do mundo em resposta à crise econômica e financeira instalada mundo afora no pós-2008. A natureza de tais medidas, em plena dissonância com o núcleo convencionado no novo consenso, permitiu a alcunha de política monetária não convencional. A tradicional interest rate policy do novo consenso macroeconômico deixou de fazer sentido uma vez atingido o limite inferior da taxa de juros, abrindo espaço para a não convencional balance sheet policy. Após uma revisão do processo de formação do novo consenso e seus preceitos, é feita uma análise dos fundamentos teóricos por trás das políticas não convencionais. De forma a complementar e direcionar o trabalho, é feito, por fim, um estudo de caso envolvendo o Federal Reserve e o Banco Central Europeu em suas experiências com o novo leque de políticas que se abriu na eventualidade da crise

Kinetics of copper passivation and pitting corrosion in Na2SO4 containing dilute NaOH aqueous solution

The electrochemical behaviour of Cu in alkaline solutions containing Na2SO4 was studied using potentiodynamic and potentiostatic techniques complemented by scanning electron microscopy. The presence of Na2SO4 enhances Cu electrodissolution through the passive layer and decreases the breakdown potential. There is a critical OH-/sulphate concentration ratio for the onset of localized corrosion. The competitive interaction between OH- and sulphate ions at the passive layer can explain the experimental data. Pit initiation fits the point defect model for passivity breakdown. Pit growth involves a number of current contributions which can be distinguished through the analysis of current transients at constant potential by using nucleation and growth models.Instituto de Investigaciones Fisicoquímicas Teóricas y AplicadasFacultad de Ciencias Exacta

Shortcomings of international standard iso 9223 for the classification, determination, and estimation of atmosphere corrosivities in subtropical archipelagic conditions—The case of the Canary Islands (Spain)

grant ProID2017010042The classification, assessment, and estimation of the atmospheric corrosivity are fixed by the ISO 9223 standard. Its recent second edition introduced a new corrosivity category for extreme environments CX, and defined mathematical models that contain dose–response functions for normative corrosivity estimations. It is shown here that application of the ISO 9223 standard to archipelagic subtropical areas exhibits major shortcomings. Firstly, the corrosion rates of zinc and copper exceed the range employed to define the CX category. Secondly, normative corrosivity estimation would require the mathematical models to be redefined introducing the time of wetness and a new set of operation constants.publishersversionpublishe

Nervous Necrosis Virus (NNV) Booster Vaccination Increases Senegalese Sole Survival and Enhances Immunoprotection

iral encephalopathy and retinopathy (VER), caused by nervous necrosis virus (NNV), is a serious threat to Senegalese sole farming. We have previously demonstrated that immunization with an inactivated vaccine confers partial protection against the infection. However, a vaccination program must be finely adjusted to achieve the best results in terms of immune system stimulation and protection. In this study we show that a booster injection 30 days after prime vaccination increases sole survival and reduces NNV replication in brain (viral target organ). The analysis of immune-related genes expression indicated that T CD4+ lymphocytes and the proteins Mx and HERC4 may play an important role in the protection. These findings increase our understanding of sole immune response against NNV and may contribute to the development of effective protection measures.This research was funded by Ministerio de Ciencia, Innovación y Universidades (MCIUI), the Agencia Estatal de Investigación (AEI) and FEDER, grant number RTI2018-094687-B-C21. Dr. Sandra Souto was funded with a postdoctoral grant from Consellería de Cultura, Educación e Universidade, Xunta de Galicia (grant number: ED481D-2022-024). Partial funding for open access charge: Universidad de Málag

Senegalese sole immune response against betanodavirus recombinants harboring modifications in the 3' terminal region of the RNA1

The nervous necrosis virus (NNV) is the etiological agent of the viral nervous necrosis (VNN), a disease affecting a high number of fish species worldwide. NNV genome is composed of two segments RNA1 and RNA2, encoding the RNA-dependent RNA polymerase and the capsid protein, respectively. NNV has been classified into four species: SJNNV, TPNNV, RGNNV and BFNNV. Furthermore, reassortants between RGNNV and SJNNV have been reported, such as wt160 isolated from Senegalese sole, which presents a RGNNV-RNA1 and a SJNNV-RNA2 type segments, and causes 100% mortality in this fish species. This isolate exhibited differences in the 3’ NCR of both genomic segments when compared to the reference strains of each genotype. In this study, the effect on virulence of the substitutions observed in the 3’NCR of the wt160-RNA1 has been evaluated, by the development of two recombinants harbouring mutations at position 3073 and 3093, which make the wt160-RNA1 similar to the reference RGNNV. Moreover, immune response of sole against the infection with these recombinants compared to the wild-type, has been evaluated using an OpenArray. The infection with the recombinants r3073 and r3093 decreased the mortality to 29.3% and 25.3%, respectively. Furthermore, the number of DEGs was higher at 3 days than at 2 days p.i., after the infection with the three viruses, being the number of DEG quite similar among viruses. Significant differences between DEG fold changes after infection with the mutants and the wt160 will be discussed. It should be highlighted that at 2 days p.i., the gene gig1 was not expressed after the infection with r3073 and r3093. However, at 3 days p.i. this gene was expressed at the highest level after the infection with the three viruses. Moreover, the infection with the wt160 induced the down-regulation of the genes gilt and magel2, which was not observed after the infections with r3073.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Electrochemical behaviour of copper in aqueous moderate alkaline media, containing sodium carbonate and bicarbonate, and sodium perchlorate

The voltammetric polarization of Cu specimens in Na2CO3, NaHCO3 and NaClO4 solutions (8-12pH range) has been investigated. Voltammetry data were complemented with SEM and electron microprobe analysis. Results are found to be in agreement with the passivation model developed for Cu in plain NaOH solutions. For the latter the process can be described in terms of two steps, namely, at low potentials the initial formation of a Cu2O thin layer followed by the growth of a massive Cu2O layer, and at higher potentials the appearance of a CuO-Cu(OH)2 layer. These processes are accompanied by the formation of soluble Cu species. Beyond a certain potential which increases with the solution pH, copper pitting takes place. This model can be extended to Cu in carbonate/bicarbonate containing solutions by considering that Cu carbonates precipitate as long as soluble ionic Cu species are produced, without interfering appreciably with the formation of Cu oxides. The appearance of copper carbonate species is enhanced when pitting corrosion sets in. The precipitation of Cu carbonates occurs principally around pits. Cu pitting, although it is observed for all solutions, becomes more noticeable at the lowest pH values. At a constant pH, the density of pits increases in the order NaClO4 > NaHCO3 > Na2CO3. The influence of the electrolyte composition on Cu pitting is closely related to the blockage capability for pit nucleation and growth of the corresponding copper salts. Passivation in the Cu2O-Cu(OH)2 region hinders pitting corrosion.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA)Facultad de Ciencias Exacta

Electrochemical behaviour of copper in aqueous moderate alkaline media, containing sodium carbonate and bicarbonate, and sodium perchlorate

The voltammetric polarization of Cu specimens in Na2CO3, NaHCO3 and NaClO4 solutions (8-12pH range) has been investigated. Voltammetry data were complemented with SEM and electron microprobe analysis. Results are found to be in agreement with the passivation model developed for Cu in plain NaOH solutions. For the latter the process can be described in terms of two steps, namely, at low potentials the initial formation of a Cu2O thin layer followed by the growth of a massive Cu2O layer, and at higher potentials the appearance of a CuO-Cu(OH)2 layer. These processes are accompanied by the formation of soluble Cu species. Beyond a certain potential which increases with the solution pH, copper pitting takes place. This model can be extended to Cu in carbonate/bicarbonate containing solutions by considering that Cu carbonates precipitate as long as soluble ionic Cu species are produced, without interfering appreciably with the formation of Cu oxides. The appearance of copper carbonate species is enhanced when pitting corrosion sets in. The precipitation of Cu carbonates occurs principally around pits. Cu pitting, although it is observed for all solutions, becomes more noticeable at the lowest pH values. At a constant pH, the density of pits increases in the order NaClO4 > NaHCO3 > Na2CO3. The influence of the electrolyte composition on Cu pitting is closely related to the blockage capability for pit nucleation and growth of the corresponding copper salts. Passivation in the Cu2O-Cu(OH)2 region hinders pitting corrosion.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA)Facultad de Ciencias Exacta

Deep-Sync: A novel deep learning-based tool for semantic-aware subtitling synchronisation

Subtitles are a key element to make any media content accessible for people who suffer from hearing impairment and for elderly people, but also useful when watching TV in a noisy environment or learning new languages. Most of the time, subtitles are generated manually in advance, building a verbatim and synchronised transcription of the audio. However, in TV live broadcasts, captions are created in real time by a re-speaker with the help of a voice recognition software, which inevitability leads to delays and lack of synchronisation. In this paper, we present Deep-Sync, a tool for the alignment of subtitles with the audio-visual content. The architecture integrates a deep language representation model and a real-time voice recognition software to build a semantic-aware alignment tool that successfully aligns most of the subtitles even when there is no direct correspondence between the re-speaker and the audio content. In order to avoid any kind of censorship, Deep-Sync can be deployed directly on users' TVs causing a small delay to perform the alignment, but avoiding to delay the signal at the broadcaster station. Deep-Sync was compared with other subtitles alignment tool, showing that our proposal is able to improve the synchronisation in all tested cases.This work has been supported by the Spanish Ministry of Science and Education under TIN2017-85727-C4-3-P grant (DeepBio) and Comunidad Autónoma de Madrid under S2018/TCS-4566 grant (CYNAMON). We gratefully acknowledge the support of NVIDIA Corporation with the donation of the Titan V GPU used for this research