New constraints on geomagnetic field intensity variations in the Balkans during the Early Byzantine period from ceramics unearthed at Thasos and Delphi, Greece

We report on five new archeomagnetic field intensity data obtained in Greece from groups of pottery fragments precisely dated to between the middle of the fourth century and the beginning of the seventh century CE. These potsherds were unearthed on the island of Thasos (Northern Greece) and at Delphi (Central Greece). Their dating is primarily ensured by typo-morphological arguments, combined with archeological and historical constraints. Archeointensity measurements were performed using the Triaxe protocol, which involves continuous magnetization measurements at high temperatures and which allows us to overcome the thermoremanent magnetization anisotropy and cooling rate effects. Magnetic mineralogy measurements such as low-field magnetic susceptibility versus temperature and thermal demagnetization of three orthogonal IRM components have identified magnetite with possible impurities as the main carrier of the magnetization. The new data range from 52.0μT to 61.5μT after reduction to Thessaloniki and show an increase in geomagnetic field intensity in Greece during the Early Byzantine period. They appear in good agreement with previous intensity results satisfying a set of quality criteria and obtained in a region of 700 km around Thessaloniki, therefore incorporating data from Bulgaria, Greece and South Italy. This study is part of an ongoing effort to better constrain the evolution in geomagnetic field intensity in the Balkans over the past few millennia, with potential use for dating in archeology. The rapid intensity variations documented here during the Early Byzantine period are clearly of interest in this respect

Spectroscopic study of MATLAS-2019 with MUSE:An ultra-diffuse galaxy with an excess of old globular clusters

The MATLAS deep imaging survey has uncovered a plethora of dwarf galaxies in the low density environment it has mapped. A fraction of them are unusually extended and have a low-surface brightness. Among these so-called ultra-diffuse galaxies, a few seem to host an excess of globular clusters. With the integral-field unit spectrograph MUSE we have observed one of these galaxies - MATLAS J15052031+0148447 (MATLAS-2019) - located towards the nearby group NGC 5846 and measured its systemic velocity,age, and metallicity, and that of its globular clusters candidates. For the stellar body of MATLAS-2019 we derive a metallicity of -1.33+0.19-0.01 dex and an age of 11.2+1.8-0.8 Gyr. For some of the individual GCs and the stacked GC population, we derive consistent ages and metallicities. From the 11 confirmed globular clusters and using a Markov Chain Monte Carlo approach we derived a dynamical mass-to-light ratio of 4.2+8.6-3.4M/L. This is at the lower end of the luminosity-mass scaling relation defined by the Local Group dwarf galaxies. Furthermore, we couldn't confirm nor reject the possibility of a rotational component of the GC system. If present, this would further modify the inferred mass. Follow-up observations of the globular cluster population and of the stellar body of the galaxy are needed to assess whether this galaxy is lacking dark matter like it was suggested for the pair of dwarf galaxies in the field of NGC 1052, or if this is a miss-interpretation arising from systematic uncertainties of the method commonly used for these systems and the large uncertainties of the individual globular cluster velocities.Comment: 10 pages, 9 figures, 2 tables, accepted for publication in A&

Mutations et permanence architecturales au cœur de Thasos (VIIIe s. av. J.-C. – VIIe s. apr. J.-C.)

Η περιοχή ανάμεσα στην Αρχαία Αγορά, το Διονύσιο και το Αρτεμίσιο στη Θάσο έτυχε ενδελεχούς ανασκαφικής έρευνας ήδη από τα πρώτα έτη της παρουσίας Γάλλων αρχαιολόγων στο νησί στις αρχές του 20ου αι. που συνεχίζεται ως τις μέρες μας. Την περίοδο προ της ελεύσεως των Παρίων αποίκων και τον πρώτο αιώνα μετά την ίδρυση της αποικίας ο χώρος ήταν εργαστηριακός. Τον 6ο ή 5ο αι. π.Χ. κτίζεται ένα κτήριο που παραμένει σε χρήση, παρά τις αλλαγές και προσθήκες, ως τον 4ο αι. π.Χ. Στα τέλη του αιώνα αυτού το κτήριο ενσωματώνεται σε ένα μεγάλο ιδιωτικό οίκημα που κτίζεται αδιαφορώντας για την υπάρχουσα ρυμοτομία και παραμένει σε χρήση ως τις πρώτες δεκαετίες του 7ου αι. μ.Χ. Επομένως, η περιοχή που εξετάζουμε επιβιώνει οικιστικά για περισσότερους από 13 αιώνες

Genomics and transcriptomics yields a system-level view of the biology of the pathogen Naegleria fowleri

Background The opportunistic pathogen Naegleria fowleri establishes infection in the human brain, killing almost invariably within 2 weeks. The amoeba performs piece-meal ingestion, or trogocytosis, of brain material causing direct tissue damage and massive inflammation. The cellular basis distinguishing N. fowleri from other Naegleria species, which are all non-pathogenic, is not known. Yet, with the geographic range of N. fowleri advancing, potentially due to climate change, understanding how this pathogen invades and kills is both important and timely. Results Here, we report an -omics approach to understanding N. fowleri biology and infection at the system level. We sequenced two new strains of N. fowleri and performed a transcriptomic analysis of low- versus high-pathogenicity N. fowleri cultured in a mouse infection model. Comparative analysis provides an in-depth assessment of encoded protein complement between strains, finding high conservation. Molecular evolutionary analyses of multiple diverse cellular systems demonstrate that the N. fowleri genome encodes a similarly complete cellular repertoire to that found in free-living N. gruberi. From transcriptomics, neither stress responses nor traits conferred from lateral gene transfer are suggested as critical for pathogenicity. By contrast, cellular systems such as proteases, lysosomal machinery, and motility, together with metabolic reprogramming and novel N. fowleri proteins, are all implicated in facilitating pathogenicity within the host. Upregulation in mouse-passaged N. fowleri of genes associated with glutamate metabolism and ammonia transport suggests adaptation to available carbon sources in the central nervous system. Conclusions In-depth analysis of Naegleria genomes and transcriptomes provides a model of cellular systems involved in opportunistic pathogenicity, uncovering new angles to understanding the biology of a rare but highly fatal pathogen.publishedVersio

Reconstruction of Oomycete Genome Evolution Identifies Differences in Evolutionary Trajectories Leading to Present-Day Large Gene Families

The taxonomic class of oomycetes contains numerous pathogens of plants and animals but is related to nonpathogenic diatoms and brown algae. Oomycetes have flexible genomes comprising large gene families that play roles in pathogenicity. The evolutionary processes that shaped the gene content have not yet been studied by applying systematic tree reconciliation of the phylome of these species. We analyzed evolutionary dynamics of ten Stramenopiles. Gene gains, duplications, and losses were inferred by tree reconciliation of 18,459 gene trees constituting the phylome with a highly supported species phylogeny. We reconstructed a strikingly large last common ancestor of the Stramenopiles that contained ∼10,000 genes. Throughout evolution, the genomes of pathogenic oomycetes have constantly gained and lost genes, though gene gains through duplications outnumber the losses. The branch leading to the plant pathogenic Phytophthora genus was identified as a major transition point characterized by increased frequency of duplication events that has likely driven the speciation within this genus. Large gene families encoding different classes of enzymes associated with pathogenicity such as glycoside hydrolases are formed by complex and distinct patterns of duplications and losses leading to their expansion in extant oomycetes. This study unveils the large-scale evolutionary dynamics that shaped the genomes of pathogenic oomycetes. By the application of phylogenetic based analyses methods, it provides additional insights that shed light on the complex history of oomycete genome evolution and the emergence of large gene families characteristic for this important class of pathogens

Fios narrativos: uma leitura sobre personagens que leem

Esse estudo é sobre leitores, leitura, personagens leitoras. A pergunta que nos inquieta é como e o que lê uma personagem que representa uma espécie de consenso sobre quem seria um leitor culto. Nesse emaranhado de procedimentos para entender a ficção, é importante ter vistas à produção de sentidos possíveis em um processo de identificação/estranhamento com as referências, os valores e a reorganização de um universo simbólico e linguístico dos romances sobre os quais nos debruçamos, especificamente a partir de uma personagem específica da série Um Castelo no Pampa, de Luiz Antonio de Assis Brasil. Trata-se de um contraditório senhor do século, Olímpio, e outras personagens que o rodeiam e justificam. Nesse processo, nós, enquanto críticos, podemos ser amparadas pelo conceito de representações (CHARTIER, 2009), para articular categorias de análise que privilegiem as modalidades e procedimentos de leitura, os repertórios de leitura dessa personagem – vislumbrando que isso ofereça rico material para a reflexão acerca dos papeis sociais que configuram a sua criação

Global genetic diversity status and trends: towards a suite of Essential Biodiversity Variables (EBVs) for genetic composition

Biodiversity underlies ecosystem resilience, ecosystem function, sustainable economies, and human well-being. Understanding how biodiversity sustains ecosystems under anthropogenic stressors and global environmental change will require new ways of deriving and applying biodiversity data. A major challenge is that biodiversity data and knowledge are scattered, biased, collected with numerous methods, and stored in inconsistent ways. The Group on Earth Observations Biodiversity Observation Network (GEO BON) has developed the Essential Biodiversity Variables (EBVs) as fundamental metrics to help aggregate, harmonize, and interpret biodiversity observation data from diverse sources. Mapping and analyzing EBVs can help to evaluate how aspects of biodiversity are distributed geographically and how they change over time. EBVs are also intended to serve as inputs and validation to forecast the status and trends of biodiversity, and to support policy and decision making. Here, we assess the feasibility of implementing Genetic Composition EBVs (Genetic EBVs), which are metrics of within-species genetic variation. We review and bring together numerous areas of the field of genetics and evaluate how each contributes to global and regional genetic biodiversity monitoring with respect to theory, sampling logistics, metadata, archiving, data aggregation, modeling, and technological advances. We propose four Genetic EBVs: (i) Genetic Diversity; (ii) Genetic Differentiation; (iii) Inbreeding; and (iv) Effective Population Size (Ne). We rank Genetic EBVs according to their relevance, sensitivity to change, generalizability, scalability, feasibility and data availability. We outline the workflow for generating genetic data underlying the Genetic EBVs, and review advances and needs in archiving genetic composition data and metadata. We discuss how Genetic EBVs can be operationalized by visualizing EBVs in space and time across species and by forecasting Genetic EBVs beyond current observations using various modeling approaches. Our review then explores challenges of aggregation, standardization, and costs of operationalizing the Genetic EBVs, as well as future directions and opportunities to maximize their uptake globally in research and policy. The collection, annotation, and availability of genetic data has made major advances in the past decade, each of which contributes to the practical and standardized framework for large-scale genetic observation reporting. Rapid advances in DNA sequencing technology present new opportunities, but also challenges for operationalizing Genetic EBVs for biodiversity monitoring regionally and globally. With these advances, genetic composition monitoring is starting to be integrated into global conservation policy, which can help support the foundation of all biodiversity and species' long-term persistence in the face of environmental change. We conclude with a summary of concrete steps for researchers and policy makers for advancing operationalization of Genetic EBVs. The technical and analytical foundations of Genetic EBVs are well developed, and conservation practitioners should anticipate their increasing application as efforts emerge to scale up genetic biodiversity monitoring regionally and globally