Search results for "Mount"

Evidence for cryptic glacial refugia from North American mountain sheep mitochondrial DNA

2006

The separation of populations by ice sheets into large refugia can account for much of the genetic diversity found in present day populations. The evolutionary implications of small glacial refugia have not been as thoroughly explored. To examine refugial origins of North American mountain sheep Ovis spp., we analyzed a 604 bp portion of the mitochondrial DNA (mtDNA) control region from 223 O. dalli and O. canadensis. Major refugia were identified in eastern Beringia and southern North America, and we found evidence for two smaller refugia situated between the Laurentide and Cordilleran glaciers. Our results are the first to demonstrate support for survival of any organism in the latter two…

La Neolitización en Cantabria

2019

El territorio actual de la región de Cantabria se corresponde fundamentalmente con el sector central de la Cornisa Cantábrica, además de los valles de Campóo y Valderredible y como la práctica totalidad de trabajos de síntesis realizados tanto en el País Vasco, como en Asturias se circuscriben a sus límites regionales se ha convertido en un importante vacío de información para el estudio del proceso de neolitización en la Cornisa Cantábrica, la poca atención que se ha dispensado a los datos arqueológicos regional origina que las teorías generales sobre el proceso, o los procesos de neolitización en la Cornisa Cantábrica tengan serias lagunas. Con este breve artículo pretendemos contribuir a…

A new species ofCentaurea(Asteraceae) from Sicily

2008

A new species of Centaurea, Centaurea sicana, endemic to Sicily, is described. This new taxon is close to Centaurea parlatoris and Centaurea giardinae (Sect. Dissectae), the former occurring at Palermo and in the Madonie Mountains, while the latter occurs on the Etna volcano. The new species has so far been found only on the Sicani Mountains, a limestone mountain range in western Sicily, while the related species occur in the surrounding mountains. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 157, 785–788.

Reviewing the identity of the Maltese Polypodium (Polypodiaceae) – new evidence from morphology and flow cytometry

2020

The first record of Polypodium from Gozo (Maltese Islands) was described as a new endemic taxon, Polypodium vulgare subsp. melitense, based on its unique set of morphological characters. It was treated as a novelty and designated as a subspecies of P. vulgare mainly due to the lack of paraphyses, the presence of 10–16 annular cells, and a mean spore length of 64 μm. The fern was reassessed by us employing a more rigid morphological analysis and the application of flow cytometry. The absence of paraphyses was confirmed, but the number of annular cells (5–11) and the spore length (70–79 μm) differed from the previous study. These and other morphological traits, the phenology (leaf-shedding in…

COMPOSITION OF THE ESSENTIAL OILS IN CALENDULA SUFFRUTICOSA (ASTERACEAE) FROM SICILY

2016

The genus Calendula L. (Calenduleae Cass., Asteraceae) includes several species having medicinal properties. Pharmacological studies reveal, for instance, that C. officinalis L. exhibits antibacterial, antiviral, antinflammatory, antitumor and antioxidant properties; C. arvensis L. has antibacterial, antinflammatory, antimutagenic and haemolytic activities; C. suffruticosa Vahl has antimicrobial activity, especially against pathogenic microorganisms as Pseudomonas syringae Van Hall, Pseudomonas fluorescens (Flügge) Migula, Xanthomonas campestris (Pammel) Dowson and Agrobacterium tumefaciens Smith & Townsend. Nevertheless, despite a long tradition of use of the above species, and others,…

THE LEARNING AND TEACHING OF THE CONCEPTS ‘AMOUNT OF SUBSTANCE’ AND ‘MOLE’: A REVIEW OF THE LITERATURE

2002

The importance of the concepts of ’amount of substance’ and ’mole’ is supported by the abundance in the last decade of research papers on the problem of the teaching and learning of these concepts. The present study attempts a review of the relevant bibliography, including recent investigations on both the difficulties of learning these concepts and the didactic alternatives that are provided from different perspectives. The literature reviewed shows that students have great difficulty in handling the above concepts. In addition, a clear discrepancy exists between what is assumed as correct by the scientific community and the thinking of educators. Finally, strategies for the teaching of th…

A Mountain Pass Theorem for a Suitable Class of Functions

2009

Coat darkness is associated with social dominance and mating behaviour in a mountain sheep hybrid lineage

2008

Natural hybridization can produce novel traits when morphologically different populations hybridize, and can introduce variation in traits that become associated with sexual selection. Evidence from breeding experiments and genetic markers indicate that the great variation in coat darkness and the unique coat patterns found in Stone's sheep Ovis dalli stonei, populations, have resulted from an ancient hybridization event between thinhorn sheep, O. dalli, and bighorn sheep, O. canadensis. Behavioural evidence gathered in 2003 and 2004 in Yukon Territory, Canada, showed that higher dominance rank was correlated with increasing darkness in rams, and comparatively darker rams were seen more oft…

Comparative assessment of spatial perception in augmented reality depending on the consistency of depth cues

2021

Discrepancies between depth cues (accommodation and vergence) is one of the major issues caused in a stereoscopic augmented reality at close viewing distances. It adversely affects not only user comfort but also spatial judgements. Images with consonant cues at different distances have become available due to the implementation of multifocal architecture in the head-mounted displays, although its effect on spatial perception has remained unknown. In this psychophysical study, we investigated the effects of consonant and conflicting depth cues on perceptual distance matching in the stereoscopic environment of augmented reality using a head-mounted display that was driven in two modes: multif…

Simulations of convectively-driven density currents in the Atlas region using a regional model: Impacts on dust emission and sensitivity to horizonta…

2009

[1] During the SAMUM field campaign in southern Morocco in May and June 2006 density currents generated by evaporative cooling after convective precipitation were frequently observed at the Sahara side of the Atlas Mountain chain. The associated strong surface cold-air outflow during such events has been observed to lead to dust mobilization in the foothills. Here a regional model system is used to simulate a density current case on 3 June 2006 and the subsequent dust emission. The model studies are performed with different parameterization schemes for convection, and with different horizontal model grid resolutions to examine to which extent the model system can be used for reproducing dus…