1,721,163 research outputs found
The first appearance of monothalamous foraminifera and the molecular clock, state of the art.
No full textWhen did foraminifera appear in the geological record? The traditional paleontological approach put the first
occurrence of Foraminifera in the Paleozoic, however the architectural complexity and design displayed by Lower
Cambrian foraminiferal assemblages joint to the low fossilization potential of soft-walled taxa, indicate that the fossil
record should not be interpreted so literally (Langer, 1999). In literature interpretations based on molecular sequencing
data (molecular clock), which use the genetic distance to estimate divergence times between lineages, suggest that the
initial appearance of foraminifera should date back to 1.1 billion years (Pawlowski et al., 2003). Finally recent
paleontological data have found also several evidence of taxa similar to soft walled saccamminids back in the post
Sturtian deposits of Namibia and Mongolia (Bosak et al., 2012). Other similar putatively organic structured organisms
are described in many other articles (Marti Mus & Moczydlowska, 2000; Porter et al., 2003; Maloof et al., 2010) and
also Late Ediacaran Agglutinated foraminifera have been found by Pazio (2012) in northern Norway, evidencing that
this topic deserve to be approached deeply, joining all the efforts in order to find new sites and fossils. Aim of this
presentation is to point out recent findings of organic walled forms which prove that a different approach in the
preparation of samples and the study of this early forms needs to be adopted
Autoantibodies from patients with systemic lupus bind a shared sequence of SmD and Epstein-Barr-virus encoded nuclear antigen EBNA I
No full textSmD is one of the small nuclear ribonucleoproteins frequently targeted by autoantibodies in systemic lupus erythematosus. We isolated and characterized the antibodies present in lupus sera that are specific for the C-terminal region of SmD (sequence 95-119). This region is highly homologous to sequence 35-58 of the EBNA I antigen, one of the nuclear antigens induced by infection with Epstein-Barr virus. Antibodies affinity purified over a peptide 95-119 column were able to recognize this sequence in the context of the whole SmD molecule, as they reacted with blotted recombinant SmD. Anti-SmD 95-119 antibodies bound also the EBNA I 35-58 peptide and detected the EBNA I molecule in a total cell extract from Epstein-Barr virus-infected lines. A population of anti-SmD antibodies is, therefore, able to bind an epitope shared by the autoantigen and the viral antigen EBNA I. To investigate the involvement of this shared epitope in the generation of anti-SmD antibodies, we immunized mice with the EBNA I 35-58 peptide. Sera from immunized animals displayed the same pattern of reactivity of spontaneously produced anti-SmD antibodies. They reacted in fact with the EBNA peptide as well as with SmD 95-119 and recombinant SmD. These data suggest that molecular mimicry may play a role in the induction of anti-SmD autoantibodies
Monothalamous soft-shelled foraminiferal image dataset from the Kveithola Trough (NW Barents Sea)
Full text linkWe present an image dataset of monothalamous soft-shelled Foraminifera (Monothalamea, [1]), an important component of benthic foraminiferal assemblage in sediment cores collected during two oceanographic expeditions that contributed to the MSM30-CORIBAR project (Ice dynamics and meltwater deposits: coring in the Kveithola trough, NW Barents Sea). 9 subsamples of sediment cores were collected during different years (2013-2016) in the Kveithola Trough, a glacially carved system in the NW Barents Sea. Cores were retrieved using a multi-corer (MUC) and a giant box-corer (GBC) and the subcores for foraminiferal analyses were obtained using Plexiglas tubes inserted manually into the cores. These subcores were sliced at 0.5 cm intervals down to 2 cm sediment depth and then every 1 cm down to 10 cm. Two staining methods, Cell Tracker Green (CTG) and Rose Bengal (RB), were used to distinguish between living and dead individuals. Then, the fixed sediment samples were sieved through 63 and 150 μm mesh screens and preserved in 10 % borax-buffered formalin. Six species and 37 undescribed morphotypes were recognized and included in this image dataset. Relatively few species of soft-shelled, monothalamous foraminifera have been described compared to a much larger number of undescribed morphotypes recognised from across the marine realm. Few researchers study with their taxonomy because of the time and difficulties that morphological identification involves. In addition, because "soft", delicate monothalamids rarely fossilize, they are generally overlooked by micropaleontologists. However, they are abundant and diverse and represent an important faunal component of marine as well as freshwater ecosystems. Further information about these frequently overlooked protists will help to address important knowledge gaps and enhance our ability to manage and conserve the planet's resources responsibly. In particular, our image dataset highlights the importance of monothalamous soft-shelled foraminifera in this peculiar Arctic environment and contributes to the first species/morphotype checklist for the area. We hope it will serve to fill gaps in knowledge regarding the ecology and biodiversity of benthic foraminifera, helping users to identify monothalamids species and morphotypes in Arctic waters and beyond. This data article is associated with the research papers: "Benthic foraminiferal assemblages and environmental drivers along the Kveithola Trough (NW Barents Sea)" by [2]
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Autoantibodies from patients with systemic lupus erythematosus bind a shared sequence of SmD and Epstein-Barr virus-encoded nuclear antigen EBNA I.
No full textSmD is one of the small nuclear ribonucleoproteins frequently targeted by autoantibodies in systemic lupus erythematosus. We isolated and characterized the antibodies present in lupus sera that are specific for the C-terminal region of SmD (sequence 95-119). This region is highly homologous to sequence 35-58 of the EBNA I antigen, one of the nuclear antigens induced by infection with Epstein-Barr virus. Antibodies affinity purified over a peptide 95-119 column were able to recognize this sequence in the context of the whole SmD molecule, as they reacted with blotted recombinant SmD. Anti-SmD 95-119 antibodies bound also the EBNA I 35-58 peptide and detected the EBNA I molecule in a total cell extract from Epstein-Barr virus-infected lines. A population of anti-SmD antibodies is, therefore, able to bind an epitope shared by the autoantigen and the viral antigen EBNA I. To investigate the involvement of this shared epitope in the generation of anti-SmD antibodies, we immunized mice with the EBNA I 35-58 peptide. Sera from immunized animals displayed the same pattern of reactivity of spontaneously produced anti-SmD antibodies. They reacted in fact with the EBNA peptide as well as with SmD 95-119 and recombinant SmD. These data suggest that molecular mimicry may play a role in the induction of anti-SmD autoantibodies
Analisi genetica di cavità naturali nelle evaporiti messinane del Bolognese: 2° Grotta del Prete Santo e Risorgente dell'Acquafredda
No full textA previous work presented a genetical interpretation of die Spipola’’ gypsum cave (Croara area, Bologna, Italy) based on structural and stratigraphic data collected inside the cavity. This work presents a similar genetical interpretation of caves belonging to the same karst system (‘‘Spipola-Acquafredda’’ system), namely the Prete Santo’’ and “Risorgente dell’Acquafredda’’ caves. We have studied the relationship between the trend of fractures and faults and the preferential developement of caves and related the various cave’s levels to the main thick gypsum beds and to the ‘‘Spipola’’ cave’s levels
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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