Search results for " barre"
showing 10 items of 45 documents
Problems in the identity of "Crioceras" barremense Kilian, 1895 (Ancyloceratida, Late Barremian), and their proposed resolution
2010
17 pages; The study of "Crioceras" barremense KILIAN was undertaken as a part of the revision of the Hemihoplitidae. This species was considered "classic" and has been used as the index of an Upper Barremian subzone; this usage raises a number of problems. The type specimen from Tyrol was a fragment described and illustrated by UHLIG as Crioceras sp. ind. aff. roemeri. This specimen could not be retrieved, and a topotype could not be collected. Our study revealed that there is both a biostratigraphic hiatus and important differences between conceptions of this species: (1) that ascribed UHLIG's type specimen (Upper Barremian, Tyrol), (2) KILIAN's concept of the specimen he found and named "…
Pseudoshasticrioceras bersaci nov. sp. (Ammonoidea, Gassendiceratinae), and new ammonite biohorizon for the Upper Barremian of southeastern France
2009
International audience; Research in the Feraudianus Subzone of the Sartousiana Zone of the Barremian stage led to the discovery of a new species of Pseudoshasticrioceras: P. bersaci nov. sp. Its study provides evidence concerning the developments of the latest Gassendiceratinae BERT et alii, 2006, and the relationship between the genus Pseudoshasticrioceras DELANOY, 1998, and Gassendiceras BERT et alii, 2006. In particular, this new species is derived from Pseudoshasticrioceras magnini (DELANOY, 1992) by a minor revision in the processes of ontogenesis (retardation of ornamentation - neoteny). However, the evolution towards Pseudoshasticrioceras autrani DELANOY, 1998, implies a "failure" in…
Warmer temperatures reduce the influence of an important keystone predator
2017
Predator–prey interactions may be strongly influenced by temperature variations in marine ecosystems. Consequently, climate change may alter the importance of predators with repercussions for ecosystem functioning and structure. In North-eastern Pacific kelp forests, the starfish Pycnopodia helianthoides is known to be an important predator of the purple sea urchin Strongylocentrotus purpuratus. Here we investigated the influence of water temperature on this predator–prey interaction by: (i) assessing the spatial distribution and temporal dynamics of both species across a temperature gradient in the northern Channel Islands, California, and (ii) investigating how the feeding rate of P. heli…
Micropredation on sea urchins as a potential stabilizing process for rocky reefs
2012
Rocky reefs can shift from forest, a state dominated by erect algae with high biodiversity, to barren, an impoverished state dominated by encrusting algae. Sea urchins, abundant in barrens, are usually held responsible for the maintenance of this state. Predation by large fish can revert the barren state to forest by controlling sea urchin populations. However, the persistence of a community state sometimes seems to be independent from the presence of such large predators, suggesting the existence of other, unknown mechanisms ensuring their stability. Theoretical studies suggest that the settler stage of sea urchins is determinant for maintaining a given rocky reef state. In this study, we …
Early miR-223 Upregulation in Gastroesophageal Carcinogenesis
2017
Objectives: To test miR-223 upregulation during gastric (intestinal-type) and Barrett esophageal carcinogenesis. Methods: miR-223 expression was assessed by quantitative reverse transcription polymerase chain reaction in a series of 280 gastroesophageal biopsy samples representative of the whole spectrum of phenotypic changes involved in both carcinogenetic cascades. The results were further validated by in situ hybridization on multiple tissue specimens obtained from six surgically treated gastroesophageal adenocarcinomas. miR-223 expression was also assessed in plasma samples from 30 patients with early stage (ie, stages I and II) gastroesophageal adenocarcinoma and relative controls. Res…
ACTIVIDAD FÍSICA Y DISCAPACIDAD: UN ESTUDIO CUALITATIVO CON MUJERES EN UN GIMNASIO ADAPTADO
2017
Este estudio explora cómo un grupo de mujeres con discapacidad (n=6) experimentan y perciben la práctica de actividad física en un gimnasio adaptado. Se utilizaron entrevistas semi-estructuradas como instrumento de recogida de datos cualitativos y se realizó un análisis temático inductivo. Los resultados se agruparon en torno a cuatro categorías temáticas emergentes: condición física y autonomía personal; papel paliativo del ejercicio; bienestar psicológico; relación social y apoyo. Destaca la experiencia satisfactoria de las participantes, en la que predomina una valoración positiva de procesos autorregulativos, la concepción social-relacional de la actividad física, y la relevancia del gi…
The phenotype of gastric mucosa coexisting with Barrett's oesophagus.
2001
Barrett's oesophagus complicates the gastro-oesophageal acid reflux. Helicobacter pylori infection, particularly with cagA positive strains, induces inflammatory/atrophic lesions of the gastric mucosa, which may impair acid output. No systematic study has investigated the phenotype of the gastric mucosa coexisting with Barrett's oesophagus. This study was designed to identify the phenotype of gastric mucosa associated with Barrett's oesophagus.In this retrospective case control study, the phenotype of the gastric mucosa was histologically characterised in 53 consecutive patients with Barrett's oesophagus and in 53 (sex and age matched) non-ulcer dyspeptic controls. Both patients and control…
Aurora-A overexpression as an early marker of reflux-related columnar mucosa and Barrett's oesophagus.
2007
Abstract BACKGROUND: The development of oesophageal adenocarcinoma is generally closely associated with the presence of a specialised intestinal-type epithelium such as that found in Barrett's oesophagus (BO). A particular histological condition is when the distal oesophagus showing cardiac and/or fundic mucosa without intestinal metaplasia cannot be defined as 'Barrett's mucosa' [condition that we call 'columnar-lined oesophagus' (CLO)] and up till now, there has been no agreement in literature about the management of this condition. Aurora-A overexpression leads to centrosome amplification, chromosomal instability and aneuploidy in mammalian cells. PATIENTS AND METHODS: A prospective stud…
Ruolo ecologico degli Asteroidei in due comunità dell'infralitorale superiore dell'Isola di Ustica
2009
Gli asteroidi sono predatori che si ritrovano comunemente negli ecosistemi marini di fondo duro e mobile. Nell’Area Marina Protetta “Isola di Ustica” il divieto di raccolta del riccio edule Paracentrotus lividus nell’infralitorale superiore, ha determinato la sostituzione della comunità ad alghe fotofile erette con una comunità dominata da alghe incrostanti e ricci (barren) in gran parte dell’isola. Tre specie di asteroidi, Marthasterias glacialis, Ophidiaster ophidianus e Coscinasterias tenuispina, si ritrovano comunemente sia nell’habitat dominato dal barren che in quello dove rimangono elevate coperture ad alghe fotofile erette. Sono state studiate la distribuzione e le abitudini aliment…
I Barresi di Pietraperzia. Una corte feudale tra medioevo ed età moderna
2016
La ricerca si incentra sulla committenza artistica e in particolare sulle iniziative architettoniche promosse da una famiglia dell'alta aristocrazia feudale in Sicilia, i Barresi di Piatraperzia, un centro ubicato nell’entroterra dell’isola, attualmente in provincia di Enna. In questo luogo, dove i Barresi risiederono stabilmente, si sviluppò tra il XV e il XVI secolo una corte aristocratica colta e sofisticata, che ebbe il suo fulcro nel castello di Pietraperzia, soprattutto grazie a due membri di questa famiglia, Giovanni Antonio II e il figlio Matteo, che intrattennero rapporti con autorevoli esponenti della cultura scientifica, artistica e letteraria del tempo. Il ruolo di mecenati e fi…