Search results for "Extinction"
showing 10 items of 458 documents
Estimating the dwarfing rate of an extinct Sicilian elephant.
2021
Summary Evolution on islands, together with the often extreme phenotypic changes associated with it, has attracted much interest from evolutionary biologists. However, measuring the rate of change of phenotypic traits of extinct animals can be challenging, in part due to the incompleteness of the fossil record. Here, we use combined molecular and fossil evidence to define the minimum and maximum rate of dwarfing in an extinct Mediterranean dwarf elephant from Puntali Cave (Sicily). 1 Despite the challenges associated with recovering ancient DNA from warm climates, 2 we successfully retrieved a mitogenome from a sample with an estimated age between 175,500 and 50,000 years. Our results sugge…
Contenido de la carta individual de extinción en el marco del despido colectivo : Incidencia sobre la afectación de trabajadoras embarazadas
2021
La presente obra analiza los principales pronunciamientos judiciales en relación al contenido de la carta individual de despido derivado de un despido colectivo. Se discute sobre la conveniencia de incluir la causa en la carta, así como los criterios de selección del trabajador afectado. La cuestión tiene una especial incidencia sobre un colectivo concreto: las trabajadoras embarazadas.
Ammonoid recovery after the Permian-Triassic mass extinction: a re-exploration of morphological and phylogenetic diversity patterns.
2013
The explosive ammonoid rediversification after the Permian–Triassic mass extinction is now well understood in terms of taxonomic richness and biogeography. Using an updated dataset of Early Triassic ammonoids, we compare morphological disparity and taxonomic richness patterns at the regional and global scales. Disparity evolved similarly at both scales, suggesting a global influence of abiotic factors. Morphological diversification occurred early in the Smithian and a marked contraction of the morphospace took place during the end-Smithian extinction. We confirm that trends in disparity and richness were decoupled during the Griesbachian and Dienerian. Three macroevolutionary processes may …
Temperature effects on the IR absorption bands of hydroxyl and deuteroxyl groups in silica glass
2009
Abstract In this report we will show the changes of the band shape of the hydroxyl group (SiOH) infrared (IR) absorption band (∼3670 cm −1 ) in silica glass induced by lowering temperature in the range from 290 to 20 K. This band is considered as the overlap of several spectral components associated to the vibrational activity of hydroxyl groups in different bond configurations. By a suitable analysis of the experimental band profile in terms of different sub-bands, we studied the thermal evolution of each component and we reconsidered their assignations. For comparison we examined the SiOD absorption band (∼2710 cm −1 ) as a function of temperature as well. Our data can be interpreted as a…
Dianthus superbus as a critically endangered species in Latvia: evaluation of its growth conditions and conservation possibilities
2021
Abstract Dianthus superbus is one of the most endangered species in Latvia and is on the verge of local extinction. Therefore, the aim of this study was to inventory previously identified populations of D. superbus in Latvia and to develop activities to conserve this species in accordance with the results obtained in situ. Expeditions on 18 previously documented locations, according to the data of Nature Conservation Agency, revealed only three existing D. superbus localities in Latvia with a significant number of specimens located in the Latgale region near Silenieki. In 2020, for the first time, two more new D. superbus localities were found in the vicinity of these three approved locatio…
The impact of in-canopy wind profile formulations on heat flux estimation in an open orchard using the remote sensing-based two-source model
2010
Abstract. For open orchard and vineyard canopies containing significant fractions of exposed soil (>50%), typical of Mediterranean agricultural regions, the energy balance of the vegetation elements is strongly influenced by heat exchange with the bare soil/substrate. For these agricultural systems a "two-source" approach, where radiation and turbulent exchange between the soil and canopy elements are explicitly modelled, appears to be the only suitable methodology for reliably assessing energy fluxes. In strongly clumped canopies, the effective wind speed profile inside and below the canopy layer can strongly influence the partitioning of energy fluxes between the soil and vegetation co…
Replication of fMRI group activations in the neuroimaging battery for the Mainz Resilience Project (MARP)
2020
Abstract Motivated by the recent replicability crisis we tested replicability of functional magnetic resonance imaging (fMRI) group activations in two independent samples. An identical behavioral and fMRI test battery for the longitudinal investigation of stress resilience mechanisms was developed for the Mainz Resilience Project (MARP) and conducted in a discovery (N = 54) and a replication sample (N = 103). The test battery consisted of a stress reactivity task, a reward sensitivity task, a fear conditioning and extinction paradigm, two volitional reappraisal tasks and an emotional interference inhibition task. Replicability of group activations was tested with the Jaccard index and the I…
Sex differences in conditioned stimulus discrimination during context-dependent fear learning and its retrieval in humans: the role of biological sex…
2015
BACKGROUND: Anxiety disorders are more prevalent in women than in men. Despite this sexual dimorphism most experimental studies are conducted in male participants and studies focusing on sex differences are sparse. In addition the role of hormonal contraceptives and menstrual cycle phase in fear conditioning and extinction processes remain largely unknown. METHODS: We investigated sex differences in context-dependent fear acquisition and extinction (day 1) and their retrieval/expression (day 2). Skin conductance responses (SCRs) fear and unconditioned stimulus expectancy ratings were obtained. RESULTS: We included 377 individuals (261 women) in our study. Robust sex differences were observe…
A ventral striatal prediction error signal in human fear extinction learning.
2021
Animal studies have shown that the prediction error (PE) signal that drives fear extinction learning is encoded by phasic activity of midbrain dopamine (DA) neurons. Thus, the extinction PE resembles the appetitive PE that drives reward learning. In humans, fear extinction learning is less well understood. Using computational neuroimaging, a previous study from our group reported hemodynamic activity in the left ventral putamen, a subregion of the ventral striatum (VS), to correlate with a PE function derived from a formal associative learning model. The activity was modulated by genetic variation in a DA-related gene. To conceptually replicate and extend this finding, we here asked whether…
Where There is Smoke There is Fear-Impaired Contextual Inhibition of Conditioned Fear in Smokers
2016
The odds-ratio of smoking is elevated in populations with neuropsychiatric diseases, in particular in the highly prevalent diagnoses of post-traumatic stress and anxiety disorders. Yet, the association between smoking and a key dimensional phenotype of these disorders—maladaptive deficits in fear learning and fear inhibition—is unclear. We therefore investigated acquisition and memory of fear and fear inhibition in healthy smoking and non-smoking participants (N=349, 22% smokers). We employed a well validated paradigm of context-dependent fear and safety learning (day 1) including a memory retrieval on day 2. During fear learning, a geometrical shape was associated with an aversive electric…