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A euenantiornithine bird from the Late Cretaceous Ha?eg Basin of Romania
No full textWe present the first record of a euenantiornithine bird from Romania. A small collection of fossil remains from the Maastrichtian add to the known distribution of large euenantiornithines and descriptions of birds from the Ha?eg Basin augment the known vertebrate fauna from this famous region of Translyvania. The new specimens referred here to an indeterminate taxon of euenantiornithine further demonstrate that the larger members of this diverse Cretaceous lineage were globally distributed, as many birds are today
Biogéographie et chronologie du rhinocéros éteint Stephanorhinus etruscus (Mammalia, Rhinocerotidae) d'Eurasie
Full text linkStephanorhinus etruscus is one of the most abundantly recorded and better known Eurasian Early Pleistocene rhinoceroses. Nevertheless, the first and last appearances of this species, as well as its paleogeographic distribution, are controversial and debated in literature. S. etruscus is documented since the latest Pliocene in Spain (Las Higueruelas), Italy (Montopoli and Castelnuovo di Barardenga), France (Perrier–Les Étouaires) and Romania (Iaras˘ ¸ –Cariera Veche). During the Early Pleistocene, S. etruscus occurred in several Spanish, French and Italian localities, as well as in The Netherlands (e.g., Tegelen), Germany (e.g., Thiede), Greece (e.g.,Aivaliki) and Israel(e.g., Ubeidiya). The last appearance of S. etruscus in Eurasia is debatable. Etruscan rhino populations survived till the Jaramillo subchrone (around 1.1 Ma) in France (Bois-de-Riquet), Romania (Betfia XII) and Hungary (Osztramos 2 and 8), and close to the early–middle Pleistocene transition in Spain (Cueva Victoria, Huéscar 1, Atapuerca TD4, TD6 and TD8), and Italy (Monte delle Piche).Stephanorhinus etruscus est une espèce de rhinocéros du Pléistocène inférieur d’Eurasie parmi les plus fréquemment rencontrées et les mieux connues. Néanmoins, la première et la dernière occurrence de cette espèce, tout comme sa répartition paléogéographique, sont controversées et débattues dans les références. S. etruscus est documentée à partir de la partie terminale du Pliocène en Espagne (Las Higueruelas), en Italie (Montopoli et Castelnuovo di Barardenga), en France (Perrier–Les Étouaires) et en Roumanie (Iarăș–Cariera Veche). Pendant le Pléistocène inférieur, S. etruscus apparaît dans de nombreuses localités d’Espagne, de France et d’Italie et aussi aux Pays-Bas (e.g., Tegelen), en Allemagne (e.g., Thiede), en Grèce (e.g., Aivaliki) et en Israël (e.g., Ubeidiya). La dernière présence de S. etruscus en Eurasie fait l’objet de discussions. Les populations de rhinocéros étrusque ont survécu jusqu’au subchrone Jaramillo (environ 1,1 Ma) en France (Bois-de-Riquet), en Roumanie (Betfia XII) et en Hongrie (Osztramos 2 et 8), et à la transition Pléistocène inférieur/moyen en Espagne (Cueva Victoria, Huéscar 1, Atapuerca TD4, TD6 et TD8) et en Italie (Monte delle Piche).Fil: Pandolfi, Luca. Università Di Roma Tre; ItaliaFil: Cerdeño Serrano, Maria Esperanza. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Codrea, Vlad. University Babeș-Bolyai; RumaniaFil: Kotsakis, Tassos. Università Di Roma Tre; Itali
A dinosaurian facial deformity and the first occurrence of ameloblastoma in the fossil record
No full textDespite documentation of various types of neoplastic pathologies encountered in the vertebrate fossil record, no ameloblastic tumours have been recognised so far. Ameloblastoma is a benign neoplasic tumour with a strong preponderance for the mandible. Here, we report for the first time the presence of an ameloblastoma neoplasm in the lower jaw of a specimen referred to the derived non-hadrosaurid hadrosauroid dinosaur Telmatosaurus transsylvanicus from the uppermost Cretaceous of the Haeg Basin in Romania. The location, external appearance and internal structure of the pathological outgrowth provide clear evidence for the diagnosis of ameloblastoma in Telmatosaurus. This report extends the range of pathologies encountered in hadrosauroid dinosaurs. In addition, recognition of an ameloblastoma neoplasm in a taxon lying close to the origin of ‘duck-billed’ hadrosaurid dinosaurs confirms the predisposition of this clade towards neoplasia pathologies already in its basal members
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Using molecular modeling to engineer proteins with novel functions
Full text linkThe RCSB Protein Data Bank currently stores over 30,000 X-ray crystal structures, information that has proven invaluable in various studies that have been undertaken to analyze these proteins. My goal is to apply molecular modeling techniques in order to add new functionality to enzymes whose 3D structures are available. The standard processes for modifying the functions of proteins have traditionally remained centered on experimental work, with a heavy reliance on directed evolution. One such approach has been used by Professor Peter Schultz from the Scripps Research Institute to introduce the unnatural amino acid 3-(2-naphthyl)-L-alanine into the amber stop codon of E. coli. This approach uses positive and negative selection to wean the cells into taking up 3-(2-naphthyl)-L-alanine. In contrast, I have used a computational method to predict mutations in aminoacyl-tRNA synthetases, the enzymes responsible for joining amino acids with their respective tRNAs, that will change the affinities of those proteins. My goal is to arrive at aminoacyl-tRNA synthetases that are capable of incorporating analogs of arginine, cysteine, phenylalanine, and tryptophan instead of the natural residues. As a follow-up, I have prepared a mutant tyrosyl-tRNA synthetase and tRNA to test how well an analog of tyrosine is incorporated into proteins.
I have used an in-silico protein modeling framework developed by Professor Homme Hellinga from Duke University to tackle another outstanding problem in
molecular biology: how to recreate the high affinity of the streptavidin/biotin complex. The specificity of streptavidin is changed so that it binds preferentially to biotin derivatives. Streptavidin is a tetrameric protein, similar to the avidin protein found in egg whites, but made by the Streptomyces avidinii bacteria. Streptavidin binds tightly to the vitamin D-biotin, and forms one of the strongest naturally-occurring non-covalent interactions between a protein and an organic ligand, with a dissociation constant (Kd) on the magnitude of 10-15 M.
Because of this strong binding, the streptavidin/biotin combination has been used extensively in molecular and bioengineering studies that require the joining of different molecules that would not normally come together. One of the current limitations with using this combination is that it is only possible to specifically bring together two compounds (namely the compound attached to biotin and the compound attached to streptavidin) at any one step of an assay. The aim is to engineer orthologous pairs of mutant streptavidins and biotin analogs, each of which can be covalently attached to a distinct molecular payload depending on the end-user’s intended application. The members of one orthologous pair will not cross-react with the complementary member of another orthologous pair – in other words, a mutant streptavidin should have a relatively poor binding affinity to biotin. This provides an element of selectivity to parallel reactions performed in the same environment.Biochemistr
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
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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DNA-based molecular circuits for diagnostics and therapeutics
Full text linktextNucleic acids are a uniquely flexible and multi-faceted class of molecules that fulfill fundamental and defining tasks such as replication and determination of heritable characteristics in every living organism. From the microscopic to the gigantic, from the most primitive to the most complex, life has been both molded and served by nucleic acids.
Nucleic acid circuits straddle the realm of nature and technology. The elegance of interaction between nucleic acid molecules invites us to gain a deeper understanding of the naturally occurring systems they compose and to apply our ingenuity and foresight toward developing ever more complex synthetic systems. Nature has provided these basic building blocks, which we can now arrange – and augment – for the purpose of creating molecular-level machinery.
Here we describe some ways in which we have rationally harnessed nucleic acids. In preparation for outbreaks of novel and deadly avian influenza viruses, we used quantitative polymerase chain reaction (qPCR) to track the number of flu virus particles surviving in the presence of potential antiviral drugs. We engineered tunable on/off switches that can be used to evaluate a series of conditions for diagnostic applications or to enable ‘smart’ drugs that sense, analyze, and respond to their microenvironment.
We optimized the conditions for, and used, a unique set of guanine-rich DNA sequences called G-quadruplexes, whose enzymatic and structural properties make them prime effector candidates in diagnostic platforms. G-quadruplex folding powers isothermal DNA amplification, and the small organic molecules they bind endow G-quadruplexes with expanded catalytic abilities. We genotyped drug resistance mutations in tuberculosis via visually detectable color changes in the reaction buffer. We developed a paper fluidics assay that employs soluble and bead-immobilized nucleic acids to scan for genes in tuberculosis, and upon detection, to generate a readily observable discoloration on the paper strip.
Finally, we probed the boundary of nucleic acid circuitry by attempting to expand its language via the incorporation of unnatural nucleobases into oligonucleotide components of a catalytic hairpin assembly (CHA) circuit. We subsequently evaluated the resilience of the unnatural CHA circuit to contamination by random DNA species, such as may be encountered in clinical samples.Cellular and Molecular Biolog
Fresh- to brackish water fish faunas from continental Early Oligocene deposits in the Transylvanian Basin (Romania)
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