An oxygen isotope record of lacustrine opal from a European Maar indicates climatic stability during the Last Interglacial

The penultimate temperate period, 127–110 ka before present (BP), bracketed by abrupt shifts of the global climate system initiating and terminating it, is considered as an analogue of the Holocene because of a similar low global ice‐volume. Ice core records as well as continental and marine records exhibit conflicting evidence concerning the climate variability within this period, the Last Interglacial. We present, for the first time, a high‐resolution record of oxygen isotopes in diatom opal of the Last Interglacial obtained from the Ribains Maar in France (44°50′09″N 3°49′16″E). Our results indicate that the Last Interglacial in southwestern Europe was generally a period of climatic stability. The record shows that the temperate period was initiated by an abrupt warm event followed midway by a minor climatic transition to a colder climate. An abrupt isotopic depletion that occurs simultaneously with abrupt changes in pollen and diatom assemblages marks the end of the temperate period, and is correlative with the Melisey I stadial. Variations in the isotopic composition of lake‐water related to the isotopic composition of precipitation and evaporation dominate the biogenic opal oxygen isotope record

Unlocking the gender diversity-group performance link: the moderating role of relative cultural distance

PurposeThis study aims to shed light on the relationship between gender diversity and group performance by considering the moderating role of relative cultural distance. Drawing from the categorization-elaboration model (CEM), the authors hypothesize that gender-diverse collaborative learning groups perform better when a low level of relative cultural distance in country-level individualism-collectivism or power distance exists among group members.Design/methodology/approachTo test this hypothesis, the authors conducted a study on 539 undergraduate students organized into 94 groups. The assessment of group performance was based on scores given by external raters.FindingsThe authors found that relative cultural distance significantly moderated the gender diversity-group performance relationship such that gender diversity was positively related to group performance when the collaborative learning group included members who similarly valued individualism-collectivism or power distance (i.e. relative cultural distance was low) and was negatively related to group performance when the collaborative learning group comprised members who differently valued individualism-collectivism or power distance (i.e. relative cultural distance was high).Originality/valueThis study contributes to understanding when gender diversity is positively associated with group performance by expanding the range of previously examined diversity dimensions to include relative cultural distance in country-level individualism-collectivism and power distance

Hybrid multi-observer for improving estimation performance

Various methods are nowadays available to design observers for broad classes of systems, where the primary focus is on establishing the convergence of the estimated states. Nevertheless, the question of the tuning of the observer to achieve satisfactory estimation performance remains largely open. In this context, we present a general design framework for the online tuning of the observer gains. Our starting point is a robust nominal observer designed for a general nonlinear system, for which an input-to-state stability property can be established. Our goal is then to improve the performance of this nominal observer. We present for this purpose a new hybrid multi-observer scheme, whose great flexibility can be exploited to enforce various desirable properties, e.g., fast convergence and good sensitivity to measurement noise. We prove that an input-to-state stability property also holds for the proposed scheme and, importantly, we ensure that the estimation performance in terms of a quadratic cost is (strictly) improved. We illustrate the efficiency of the approach in improving the performance of given nominal observers in two numerical examples (Van der Pol oscillator and Lithium-Ion (Li-Ion) battery model).Comment: arXiv admin note: text overlap with arXiv:2209.1013

A late Pleistocene long pollen record from Lake Urmia, NW Iran

A palynological study based on two 100-m long cores from Lake Urmia in northwestern Iran provides a vegetation record spanning 200 ka, the longest pollen record for the continental interior of the Near East. During both penultimate and last glaciations, a steppe of Artemisia and Poaceae dominated the upland vegetation with a high proportion of Chenopodiaceae in both upland and lowland saline ecosystems. While Juniperus and deciduous Quercus trees were extremely rare and restricted to some refugia, Hippophaë rhamnoides constituted an important phanerophyte, particularly during the upper last glacial sediments. A pronounced expansion in Ephedra shrub-steppe occurred at the end of the penultimate late-glacial period but was followed by extreme aridity that favoured an Artemisia steppe. Very high lake levels, registered by both pollen and sedimentary markers, occurred during the middle of the last glaciation and upper part of the penultimate glaciation. The late-glacial to early Holocene transition is represented by a succession of Hippophaë, Ephedra, Betula, Pistacia and finally Juniperus and Quercus. The last interglacial period (Eemian), slightly warmer and moister than the Holocene, was followed by two interstadial phases similar in pattern to those recorded in the marine isotope record and southern European pollen sequences

Finite-size scaling in thin Fe/Ir(100) layers

The critical temperature of thin Fe layers on Ir(100) is measured through M\"o{\ss}bauer spectroscopy as a function of the layer thickness. From a phenomenological finite-size scaling analysis, we find an effective shift exponent lambda = 3.15 +/- 0.15, which is twice as large as the value expected from the conventional finite-size scaling prediction lambda=1/nu, where nu is the correlation length critical exponent. Taking corrections to finite-size scaling into account, we derive the effective shift exponent lambda=(1+2\Delta_1)/nu, where Delta_1 describes the leading corrections to scaling. For the 3D Heisenberg universality class, this leads to lambda = 3.0 +/- 0.1, in agreement with the experimental data. Earlier data by Ambrose and Chien on the effective shift exponent in CoO films are also explained.Comment: Latex, 4 pages, with 2 figures, to appear in Phys. Rev. Lett

Inner speech sustains predictable task switching: direct evidence in adults

It has been proposed that inner speech supports task selection in task-switching studies, especially when the need for endogenous control is increased. This has been established through the suppression of inner speech in cognitive-flexibility tasks that leads to poorer performance. The aim of this study is to quantify the role of inner speech in a flexibility task by using surface laryngeal electromyography, which, contrary to previous studies, enables participants to freely verbalise the tasks. We manipulated endogenous and exogenous flexibility in a mathematical switching task paradigm. Experiment 1 shows that inner speech acts as a support for switching and is recruited more often when the tasks are of an endogenous type. The main result of Experiment 2 that language is recruited more for the mixing cost than for the switch cost (regardless of the endogenous factor) extends past findings obtained through articulatory suppression

Utilidad de la enterotomografía en la hemorragia digestiva de origen oscuro

ResumenNuestro objetivo es describir la técnica y los hallazgos de la enterotomografía (ETC) en la hemorragia digestiva de origen oscuro (HDOO). Esta entidad constituye un sangrado digestivo que persiste o recurre sin una causa identificable tras la realización de una videoendoscopia digestiva alta (VEDA) y una colonoscopia convencional (CC). Se subclasifica en evidente (HDOO-E) u oculta (HDOO-O), según la presencia o ausencia de sangrado visible en la materia fecal. En el 40-70% de los casos el sitio de la hemorragia se encuentra en el intestino delgado. En los jóvenes prevalecen los tumores como etiología, mientras que en los de mayor edad predominan las angiodisplasias intestinales.La ETC consiste en la administración de contraste neutro de alta viscosidad por vía oral para lograr la correcta distensión de las asas del intestino delgado y/o el colon. El contraste endovenoso permite una correcta valoración y caracterización de las alteraciones con asiento en la mucosa y pared del intestino. La capacidad diagnóstica de la ETC es de aproximadamente el 40%.AbstractThe aim of this article is to describe the imaging technique and CT enterography (CTE) findings in obscure gastrointestinal bleeding (OGIB). This condition is defined as the gastrointestinal bleeding of unknown origin that persists or recurs after having performed an upper endoscopy (UE) and a conventional colonoscopy (CC). Considering the presence or absence of visible bleeding in the stool, OGIB is classified as evident (OGIB–E) or occult (OGIB–O). In 40-70% of cases the bleeding source is found in the small bowel. The most common cause in young patients is neoplastic, while they are angiodysplasias in older patients.The CTE consists of previously administering an oral neutral contrast material, which distends the small and large bowel. Intravenous contrast allows the correct visualization and interpretation of mucosal and parietal lesions. The CTE diagnostic yield is approximately 40%