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In recent years, youth across the planet have begun to mobilise, motivated by the perceived injustices associated with the causes, consequences and politics of climate change. However, education systems lag behind, preoccupied with the "what" and "how" of climate change, rather than engaging it as a social issue in which students themselves are implicated. In this paper, we share the results of our participatory research exploration into youth and climate change through an international education project, in which 99 students from 13 countries joined virtually in a climate change learning experience, culminating in the collaborative development and presentation of a White Paper to the 2018 IPCC Cities and Climate Change Conference. Grounded in a critical global citizenship education framework, this project provides a site to explore climate change education from the perspectives of diverse youth, who inform possibilities for climate change education that addresses justice, individualisation and emotionality.

Simple Summary: We used 46 individuals of the critically endangered Brazilian Merganser, currently endemic to the Cerrado biome in Brazil, to understand genetic diversity and the genealogical relationships of the captive population. By characterizing 425 genomic variants in these captive specimens, our study unveiled a significant level of inbreeding, with approximately 70% of the captive birds tracing their lineage back to the founders from just two localities. Leveraging the identified DNA variants, we also identified less inbred individuals suitable for the potential future reintroduction into the wild. The Brazilian Merganser (Mergus octosetaceus) is one of the rarest birds in South America, and it is a critically endangered Anatidae species with an estimated population of less than 250 adult individuals in the Brazilian Cerrado. A captive population was established a few years ago at Zooparque Itatiba (São Paulo state) where 46 individuals were kept, and the founding population (progenitors derived from nature) was composed of 19 of the ex situ birds, derived from the four remaining localities with wild populations in Brazil. To characterize the genetic diversity and the genealogical relationships of the captive population, it is essential to conduct appropriate ex situ management and to assist future reintroduction projects. Thus, we have identified 425 SNPs by massively parallel sequencing of ddRAD libraries that allowed us to genotype individuals of the captive population. We observed a close relatedness between 70% of the captive population and founding individuals of Jalapão and Alto Paranaiba localities, indicating the need for supplementation with individuals from other areas of Canastra and Veadeiros. Even though many captives present a high level of inbreeding, we have identified some individuals with a high genetic value (less inbred) that can be selected for the breeding program to generate individuals for a future pilot reintroduction project. [ABSTRACT FROM AUTHOR]

Simple Summary: The Brazilian merganser, a critically endangered duck species in South America, was studied using a population genomics approach. This research focused on the genetic diversity of the mergansers in the four remaining wild populations located in Central Brazil. The results showed that there is a low genetic diversity and high levels of inbreeding in individuals across all locations, with a moderate level of genetic differentiation between them. These findings highlight the need for immediate conservation actions to prevent the decline of the Brazilian merganser population and genetic erosion. Genetic monitoring can help implement appropriate in situ and ex situ management strategies to increase the species' long-term survival in its natural environment. The Brazilian merganser (Mergus octosetaceus) is one of the most endangered bird species in South America and comprises less than 250 mature individuals in wild environments. This is a species extremely sensitive to environmental disturbances and restricted to a few "pristine" freshwater habitats in Brazil, and it has been classified as Critically Endangered on the IUCN Red List since 1994. Thus, biological conservation studies are vital to promote adequate management strategies and to avoid the decline of merganser populations. In this context, to understand the evolutionary dynamics and the current genetic diversity of remaining Brazilian merganser populations, we used the "Genotyping by Sequencing" approach to genotype 923 SNPs in 30 individuals from all known areas of occurrence. These populations revealed a low genetic diversity and high inbreeding levels, likely due to the recent population decline associated with habitat loss. Furthermore, it showed a moderate level of genetic differentiation between all populations located in four separated areas of the highly threatened Cerrado biome. The results indicate that urgent actions for the conservation of the species should be accompanied by careful genetic monitoring to allow appropriate in situ and ex situ management to increase the long-term species' survival in its natural environment. [ABSTRACT FROM AUTHOR]

To support sperm production, fish testes undergo intense tissue remodelling, with endocrine, paracrine and autocrine signals regulating gonad physiology. The aim of this study was to investigate the testicular expression of insulin-like growth factor (Igf) 1 and Igf2 during spermatogenesis, and their relationship with cell proliferation and apoptosis throughout the reproductive cycle. The study was performed in male Hypostomus garmani , a catfish living in headwater rivers of the São Francisco River basin, Brazil. Spermatogenesis was analysed using histology, morphometry, immunohistochemistry and terminal deoxyribonucleotidyl transferase-mediated dUTP–digoxigenin nick end-labelling (TUNEL) analysis at different maturity stages. The results showed the proliferation of spermatogonia throughout the reproductive cycle, with a higher rate during the ripe stage. Germ and Sertoli cells expressed Igf1 at all stages of testicular maturity, Igf2 was predominant at the ripe stage and both Igf1 and Igf2 occurred at the spent stage. Caspase-3 and TUNEL analysis revealed a higher rate of apoptosis at the spent stage associated with reduced expression of Igf1 and Igf2. Sertoli cell proliferation was associated with spermatogonia and spermatocyte cysts at different stages of the reproductive cycle. Together, the data support a proliferative role for Igf1 and Igf2 in regulating testicular apoptosis in H. garmani , with cyclical variation in their expression during gonad maturation. Sperm production and male fertility depend on several factors in addition to testosterone. In this study we investigated the insulin-like growth factors that are important regulators of testicular function and found that they can control the proliferation and death of germ cells during the reproductive cycle in a fish species. These results can be applied to fish farming in order to increase the production of fish for human consumption and the conservation of endangered species. [ABSTRACT FROM AUTHOR]

Copyright of RGO: Revista Gaúcha de Odontologia is the property of RGO: Revista Gaucha de Odontologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Cuadernos del CILHA is the property of Universidad Nacional de Cuyo and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Multiscale structural and geochemical studies have been applied to understand the genesis of the Paracatu deposit in Brazil, a shallow-dipping, bulk-tonnage, vein-style low-grade Au(-Ag-Pb-Zn) orebody hosted in -1000 Ma black phyllites of the Paracatu Formation, associated with intense shearing accompanying thrusting during the -680 Ma Brasiliano orogeny. Massive to laminated quartz-sulfide-carbonate veins and associated alteration and Au mineralization formed early in the deformation history, and these veins were boudinaged during subsequent progressive increase in shear strain. Geochemical profiles across the ore allow recognition of a relatively homogeneous protolith at 100-m scales with respect to Ti, Al, Zr, V, and rare earth elements, including a footwall with protolith attributes similar to those of the ore. Oxygen, hydrogen, and sulfur isotopes do not reveal a distinctive external fluid source; rather, they reflect fluid-rock equilibration with the host phyllites during greenschist facies regional metamorphism. Detailed geochemical sampling around a prominent population of smaller boudinaged veins shows that Si, Ca, and Sr were removed and Al, K, and Ti were residually concentrated during formation of synboudinage dark selvages. This process of mass transfer occurred at scales more local than the processes responsible for ore genesis. Despite the local processes of chemical equilibration and redistribution, many of the main ore components appear externally derived at scales broader than the orebody. Gold, As, Ag, Sb, Bi and, to some extent, Pb and Zn show a strong spatial and statistical correlation with boudinaged quartz-sulfide ± carbonate veins, and these are surrounded by a broader (10-50-m vertical scale) halo of enriched K, Ba, and volatiles (loss on ignition), with depleted Na and Sr. The majority of gold is present as inclusions in pyrite and arsenopyrite within and immediately surrounding the veins, and gold-bearing pyrite shows mineral chemistry consistent with a hydrothermal origin. The main population of large veins locally preserve preboudinage, complex internal vein textures, including sulfide-rich wall-rock laminae similar to laminated fault-fill veins in many orogenic-style vein deposits. These larger veins contain most of the gold in the Paracatu resource. Metals were most likely sourced distal to the Paracatu Formation and were precipitated in sheeted shear or tensile veins during the early stages of the Brasiliano thrusting. The oblate strain recorded by the boudinaged, mineralized veins is anomalous and distinctive to Paracatu at km scales, even though the thrusting is regional. Although the orebody may have been physically dislocated by thrusting from the place where the early veins formed, the anomalous strains recorded suggest a perturbation in the footwall to the regional thrust or, perhaps, a spatially restricted competency contrast within the stratigraphy, which contributed to the localization of the present mineralization during the thrusting. [ABSTRACT FROM AUTHOR]

BACKGROUND: Most patients on long-term oxygen therapy use stationary oxygen delivery systems. It is not uncommon for guidelines to instruct patients to use tubing lengths no longer than 19.68 ft (6 m) when using an oxygen concentrator and 49.21 ft (15 m) when using cylinders. However, these concepts are not based on sufficient evidence. Thus, our objective was to evaluate whether a 98.42-ft (30-m) tubing length affects oxygen flow and FIO2 delivery from 1 cylinder and 2 oxygen concentrators. METHODS: The 3 oxygen delivery systems were randomly selected, and 1, 3, and 5 L/min flows and FIO2 were measured 5 times at each flow at the proximal and distal outlets of the tubing by a gas-flow analyzer. Paired Student t test was used to analyze the difference between flows and FIO2 at proximal and distal outlets of tubing length. RESULTS: A total of 45 flows were measured between proximal and distal outlets of the 98.42-ft (30-m) tubing. Flows were similar for 1 and 3 L/min, but distal flow was higher than proximal flow at 5 L/min (5.57 × 5.14 L/min, P < .001). FIO2 was lower at distal than proximal outlet tubing at flows 1, 3, and 5 L/min, but the mean difference between measurements was less than 1%. CONCLUSIONS: Tubing length of 98.42 ft (30 m) may be used by patients for home delivery oxygen with flows up to 5 L/min, as there were no important changes in flows or FIO2. [ABSTRACT FROM AUTHOR]

The Serra Norte Carajas banded iron-formation (BIF)-hosted iron ore deposits are located in the Carajás mineral province. The deposits are hosted in the ca. 2.7 Ga Grão Pará Group, a metamorphosed volcanic-sedimentary sequence where jaspilites are under- and overlain by basalts, both at greenschist facies conditions. They represent one of the largest high-grade (>60 wt % Fe) BIF iron ore deposits and resources in the world, with hypogene iron mineralization considered to be Paleoproterozoic. Four main open pits have, to date, produced about 1.2 billion metric tons (Bt) of high-grade iron ore with additional resources of 10 Bt. Ore types at the Serra Norte deposits include soft and hard ore; the latter consists of banded, massive and/or brecciated ores and is mainly localized along the contact with the surrounding hydrothermally altered basalts. Distinct hydrothermal alteration zones consist of veins and breccias that surround the hard ores, including: (1) an early alteration zone (distal portion of orebodies), characterized by recrystallization of jasper, formation of magnetite (± martite), and the local introduction of quartz and carbonate-sulfide (±quartz) veins; (2) intermediate alteration, synchronous with the main iron ore-forming event, which is accompanied by widespread development of martite, quartz-hematite and hematite-quartz veins, and dissolution of carbonate; and (3) proximal alteration zone having various types of hard and hard-porous hematite ores containing microplaty, anhedral, euhedral, and tabular hematite species. Locally, high-grade breccia ores contain dolomite and kut-nahorite matrices indicating carbonate introduction. High-grade ore zones contain quartz ± carbonate-hematite veins and breccias. Combined microthermometry, iron chromatography, and in situ laser ablation ICP-MS analyses on fluid inclusion assemblages from five vein types reveal that (1) early alteration vein-breccia quartz-carbonate contains high-salinity (up to 30 equiv wt % NaCl) fluid inclusions, with Ca, besides Na, K, and Mg, which were trapped at temperatures of 220° to 320°C. The quartz-hosted fluid inclusions have a wide range of Cl/Br ratios, presence of Li, base metals Cu-Pb-Zn, and Fe; (2) intermediate alteration vein quartz contains both low-salinity (Na-Fe-Mg-rich) and high-salinity (Ca-Mg-Fe-rich) fluid inclusions, with trapping temperatures of 210° to 290°C; (3) advanced alteration vein and breccia quartz-carbonate has low- to high-salinity fluid inclusions and trapping temperatures between 240° to 310°C, with the low-salinity inclusions being much more abundant in quartz. There is a gradual dilution of the metals signature in fluid inclusions from early to late- and/or advanced-stage veins and breccias. The large amount of Ca in the fluid inclusions is compatible with extensive exchange of the hydrothermal fluids with the surrounding chloritized-hematitized metabasaltic wall rock. Oxygen isotope analyses on different oxide species reveal that the heaviest δ 18OSMOW values, up to 15.2%o, are recorded for jaspilites, followed by magnetite, between -0.4 to +4.3%c, and then by different hematite species such as microplary, anhedral and tabular, which fall in the range of-9.5 to -2.4%o. These results show a progressive depletion in 18O values from the earliest introduced hydrothermal oxide magnetite toward the latest tabular hematite. The advanced alteration stage in high-grade ore displays the most depleted 18O values and represents the highest fluid/rock ratio during hydrothermal alteration. This depletion is interpreted to result from the progressive mixture of descending, heated meteoric water with ascending modified magmatic fluids. Sulfides from the distal zone of metabasaltic rocks have δ18S values close to 0%o, consistent with a magmatic origin for the sulfur. Heavier δ18S values, of up to 10.8%e, in vein sulfides hosted in jaspilite, may reflect interaction with meteoric waters or, alternatively, variations in fo2 and pH conditions during evolution of the hydrothermal fluid. Calcite-kutnahorite δ13O and δ18O values from the distal alteration zones show a large δ13O range of-5.5 to -2.4%o and a relatively narrow δ18O range of 9.3 to 11.7‰. However, dolomite matrix breccias from the advanced hydrothermal zone, i.e., ore, exhibit a wider δ18O range from 15.1 to 21.8‰ and a more restricted δ13O range from -5.0 to -3.9‰. This latter range points to a single carbon source, of possible magmatic nature, whereas the larger δ18O range suggests multiple carbon and oxygen sources. The 87Sr/86Sr ratios for carbonates from the distal and advanced hydrothennal zones range between 0.7116 to 0.7460, suggesting incorporation of strontium from multiple crustal sources, including magmatic-hydrothermal fluids. A dual magmatic-meteoric hydrothermal fluid-flow model is proposed for the hematite ores in which an early, low Cl/Br ratio, saline, ascending modified magmatic fluid, caused widespread oxidation of magnetite to hematite. Progressive influx of light δ18O meteoric water, mixing with the ascending magmatic fluids, is interpreted to have been initiated during the intermediate stage of alteration. The advanced and final hydrothermal stage was dominated by a massive influx of low-salinity meteoric water, which maintained intermediate temperatures of 240° to 310cC, and concomitant formation of the paragenetically latest tabular hematite. The giant Carajas iron deposits are unique in their setting within an Archean granite-greenstone belt and their modified magmatic-meteoric hydrothennal system, compared to the other two end-member BIF iron deposit types, namely the basin-related Hamersley type and the metamorphosed metasedimentary- basin-related Iron-Quadrangle-type. The distinct hydrothermal alteration signature present in both wall-roek basalts and jaspilites, in combination with distinct fluid chemistry signatures, particularly the low δ18O values of paragenetically late oxides indicative of massive influx of meteoric water into the high-grade orebodies, provide distinctive parameters for defining the Carajás end-member type BIF deposit class. [ABSTRACT FROM AUTHOR]

Copyright of Brazilian Journal of Biology is the property of Instituto Internacional de Ecologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Ambiente e Água is the property of Revista Ambiente e Agua and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)