Minimal generating and separating sets for O(3)-invariants of several matrices

Given an algebra $F[H]^G$ of polynomial invariants of an action of the group $G$ over the vector space $H$, a subset $S$ of $F[H]^G$ is called separating if $S$ separates all orbits that can be separated by $F[H]^G$. A minimal separating set is found for some algebras of matrix invariants of several matrices over an infinite field of arbitrary characteristic different from two in case of the orthogonal group. Namely, we consider the following cases: 1) $GL(3)$-invariants of two matrices; 2) $O(3)$-invariants of $d>0$ skew-symmetric matrices; 3) $O(4)$-invariants of two skew-symmetric matrices; 4) $O(3)$-invariants of two symmetric matrices. A minimal generating set is also given for the algebra of orthogonal invariants of three $3\times 3$ symmetric matrices.Comment: 11 page

The decline of diadromous fish in Western Europe inland waters: mains causes and consequence

Relative to the overwhelming information available on marine fisheries, inland systems have received less attention within the global fisheries crisis. The present situation however, raises serious concerns and this chapter is an attempt to summarize the status of Western European inland fisheries focused on some of the most valuable species targeted in Western Europe: diadromous fishes, including shads, salmonids and the European eel. These species have been reported to be declining over the last decades and the underlying causes appear to be related with human impact on habitat, water quality deterioration, river regularizations, introduction of invasive species, and overexploitation whereas the effects of climate change are still under debate. Overall, these species not only have economic importance but also play fundamental ecological roles in inland aquatic habitats including nutrient cycling, trophic dynamics and overall productivity. Consequently, a decline of migratory fish populations may have important direct and future consequences on the economy. Nevertheless, it also means that fewer species are present to perform critical functions and the consequences may be severe when species with disproportionately influence on biogeochemical cycles, energy fluxes and trophic dynamics are lost. In view of this, the sustainable future of inland fisheries will certainly include a compromise with biodiversity maintenance. Since for different species and types of habitat the major impacts differ, some case studies are examined and management proposals are discussed

A brief global agenda for advancing the study of molluscs

Mollusca is the second largest phylum on Earth comprising more than 90,000 species. Molluscs are responsible for key functions and services in aquatic and terrestrial ecosystems. Despite their diversity and ecological and economic importance, several knowledge gaps exist concerning their basic biology. In this mini-review, I succinctly propose a new agenda for the study of molluscs for the next decade dividing it in four major topics that need urgent attention: knowledge shortfalls, monitoring at relevant spatial and temporal scales, conservation, and education and outreach. In this time of climate and biodiversity emergency, the study of molluscs and their conservation should be a priority and we cannot ignore their intrinsic and economic importance

Fouling of European freshwater bivalves (Unionidae) by the invasive zebra mussel (Dreissena polymorpha)

1. The zebra mussel (Dreissena polymorpha) is well known for its invasive success and its ecological and economic impacts. Of particular concern has been the regional extinction of North American freshwater mussels (Order Unionoida) on whose exposed shells the zebra mussels settle. Surprisingly, relatively little attention has been given to the fouling of European unionoids. 2. We investigated interspecific patterns in fouling at six United Kingdom localities between 1998 and 2008. To quantify the effect on two pan-European unionoids (Anodonta anatina and Unio pictorum), we used two measures of physiological status: tissue mass : shell mass and tissue glycogen content. 3. The proportion of fouled mussels increased between 1998 and 2008, reflecting the recent, rapid increase in zebra mussels in the U.K. Anodonta anatina was consistently more heavily fouled than U. pictorum and had a greater surface area of shell exposed in the water column. 4. Fouled mussels had a lower physiological condition than unfouled mussels. Unlike tissue mass : shell mass ratio, tissue glycogen content was independent of mussel size, making it a particularly useful measure of condition. Unio pictorum showed a stronger decline in glycogen with increasing zebra mussel load, but had a broadly higher condition than A. anatina at the time of study (July). 5. Given the high conservation status and important ecological roles of unionoids, the increased spatial distribution and fouling rates by D. polymorpha in Europe should receive more attention.Malacological Society of London Research Grant was provided to FP to support this study. Howard Baylis and Barrie Fuller (Zoology Department, University of Cambridge) facilitated the glycogen assays. Many thanks to Philine zu Ermgassen, Rebecca Mant, Anna McIvor, Nicole Spann and Alexandra Zieritz for field and lab assistance. Special thanks to David Strayer, Alan Hildrew and an anonymous referee for helpful suggestions on the manuscript

Negative effects of Corbicula fluminea over native freshwater mussels

The global decline of freshwater mussels is related with a great variety of factors, including the introduction of invasive species. However, the possible effects of other invasive bivalves, such as the Asian clam Corbicula fluminea (Müller, 1774), remain mainly unknown and highly speculative with very few manipulative experiments addressing this issue. In this study, field and laboratory experiments were conducted to assess the possible negative effects of C. fluminea on the native freshwater mussel Unio delphinus Spengler, 1783. Growth, physiological condition, and the locomotor activity were assessed in U. delphinus at increasing C. fluminea density. U. delphinus exhibited lower growth, lower physiological condition, and higher locomotor activity at higher C. fluminea density, which may suggest that this unionid is negatively affected by C. fluminea and may be displaced to less favorable habitats. Although we were not able to establish the main mechanism(s) responsible for these results, possibilities include competition for food resources, competition for space which may result in mussel displacements and/or changes in microhabitat features as a result of bioturbation activities, and production of feces and pseudofeces by C. fluminea.N. F-R was supported from a predoctoral fellowship from the Autonomic Govern of Galicia (Xunta de Galicia Plan I2C, PRE/2013/400) and a scholarship for a research stay abroad from the University of Vigo (A.P.: 00VI 131H 481.02). RS also acknowledge the support of the strategic programme UID/BIA/ 04050/2013 (POCI-01-0145-FEDER-007569) funded by national funds through the FCT I.P. and by the ERDF through the COMPETE2020—Programa Operacional Competitividade e Internacionalização (POCI). This study was conducted as part of the project FRESHCO: Multiple implications of invasive species on Freshwater Mussel coextinction processes, supported by FCT (contract: PTDC/AGRFOR/1627/2014)

Survey of the bryophytes of a gallery forest in the National Park of Serra do Cipó, Minas Gerais, Brazil

Serra do Cipó has attracted the interest of many researchers over the years because of its unique characteristics, particularly the fact that the site represents the transition between Cerrado and Atlantic Forest. The study area of Serra do Cipó is located along a gallery forest "córrego Três Pontinhas," at 19°16'00" S and 43°32'49" W and an altitude of 1,188 m. The objective of this study was to survey the Division Bryophyta in a gallery forest within the National Park of Serra do Cipo, Minas Gerais. Collections were made during the months of November 2009 and July 2011. We found 15 families, 26 genera, 43 species, and 4 varieties of mosses. The families with the largest number of species were Leucobryaceae (10), Sematophyllaceae (9), and Calymperaceae (6). Other families included Fissidentaceae (3), Bryaceae, Pylaisiadelphaceae, Pottiaceae, and Orthotrichaceae (2 spp. each); Brachytheciaceae, Cryphaeaceae, Fabroniaceae, Helicophyllaceae, Hypnaceae, Polytrichaceae, and Sphagnaceae had only 1 sp. each. Three new records for the state of Minas Gerais were found: Acroporium caespitosum, A. longirostre, and Colobodontium vulpinum

The role of adaptive resistance in a widespread freshwater mussel species

Organism features, such as size, weight, sex and age, among others, can influence the success of parasitism. For species that depend on a host to complete their life cycle, such as freshwater mussels (Bivalvia, Unionida), understanding how these traits influence parasitism can help guide management actions aimed at improving their reproductive success, ultimately benefitting their conservation. In this study, the physiological compatibility between the duck mussel Anodonta anatina and its host fish was investigated in a simultaneous infestation experiment on four (three native and one non-native) fish species using sympatric and allopatric host strains. The success of glochidia metamorphosis in juvenile mussels was evaluated as a function of host species, strain and fish length. Successful metamorphosis was achieved in almost all fish species tested and differences were detected between allopatric and sympatric strains, with higher values found in allopatric hosts. Allopatric strains of primary hosts produce more juveniles than marginal hosts and non-native species. In addition, larger fish have lower rates of metamorphosis. The results confirm recent findings showing high variation in the metamorphosis success of A. anatina glochidia among different native and non-native hosts, both in the natural environment and in artificial laboratory infestations. Allopatric hosts were more suitable for encystment, demonstrating potential adaptive immunity, not yet observed in A. anatina. Nevertheless, A. anatina may temporarily exploit the naivety of smaller fish regardless of strain. Overall, the results suggest that mussel propagation, reproduction and reintroduction efforts should consider the mechanisms that influence adaptive immunity in fish, including differences in compatibility within and between populations of sympatric and allopatric host strains. This situation should be taken into account, as successful metamorphosis is an important factor in the selection of hosts for juvenile development, especially in efforts to propagate endangered mussel species.The authors are grateful to Fernando Miranda—Polytechnic University of Bragança for their support in the host samples and daily monitoring of the experiment. This research was supported by Portuguese FCT— Foundation for Science and Technology, Project FRESHCO: Multiple implications of invasive species on freshwater mussel co-extinction processes (contract PTDC/AGR-FOR/1627/2014-04/SAICT/2015) and FEDER under Programme PT2020 for financial support to CIMO (UID/AGR/00690/2019). FCT also supported Manuel Lopes-Lima (2020.03608.CEECIND). Rogério C. Lima dos Santos was supported by doctoral grants from the Programa de Doutorado-Sanduíche no Exterior—Coordenaç˜ao de Aperfeiçoamento de Pessoal de Nível Superior—Brasil (CAPES)—Finance Code 001.info:eu-repo/semantics/publishedVersio

Estruturas das comunidades de macroinvertebrados bentónicos presentes no estuário do Rio Lima

Dissertação de Mestrado em Ciências do Mar - Recursos Marinhos apresentada ao Instituto de Ciências Biomédicas de Abel Salazar da Universidade do Port

Formação docente e o fracasso escolar

Trabalho de Conclusão de Curso (graduação)—Universidade de Brasília, Faculdade UnB Planaltina, 2018.Este estudo tem como objetivo identificar e analisar qual é a influência da formação docente no fracasso escolar, em turmas de Ciências Naturais do 6° ano, em uma escola de Ensino Fundamental, localizada na cidade de Planaltina – DF. A partir da abordagem qualitativa foram feitas entrevistas com duas professoras de Ciências Naturais, observação das aulas dessas professoras e aplicação de um questionário aos estudantes. Além disso, obtiveram-se junto à escola os resultados escolares dos anos de 2016 e 2017. Os resultados mostram que o índice de aprovação da escola foi superior a 80% no período analisado. As professoras participantes relatam não conseguir aplicar tudo o que aprenderam na licenciatura, mas buscam adotar metodologias alternativas para promover a aprendizagem dos estudantes. Por esse estudo não foi possível afirmar que a formação docente tem influência no fracasso escolar. O referencial teórico sobre a formação docente, bem como reflexões sobre metodologias de aprendizagem foram confrontadas com as questões da realidade apresentadas nas falas das entrevistadas e nos questionários, de forma a identificar relações possíveis entre a formação docente e o fracasso escolar, porém situando esse fenômeno no contexto em que se realiza e outras interferências a que esta sujeito