In this article, we introduce a process to reconstruct a Riemann surface with boundary equipped with a linked conductivity tensor from its boundary and the Dirichlet–Neumann operator associated with ...this conductivity. When initial data come from a two- dimensional real Riemannian surface equipped with a conductivity tensor, this process recovers its conductivity structure.
Abstract
Understanding how SARS-CoV-2 spreads within the respiratory tract is important to define the parameters controlling the severity of COVID-19. Here we examine the functional and structural ...consequences of SARS-CoV-2 infection in a reconstructed human bronchial epithelium model. SARS-CoV-2 replication causes a transient decrease in epithelial barrier function and disruption of tight junctions, though viral particle crossing remains limited. Rather, SARS-CoV-2 replication leads to a rapid loss of the ciliary layer, characterized at the ultrastructural level by axoneme loss and misorientation of remaining basal bodies. Downregulation of the master regulator of ciliogenesis Foxj1 occurs prior to extensive cilia loss, implicating this transcription factor in the dedifferentiation of ciliated cells. Motile cilia function is compromised by SARS-CoV-2 infection, as measured in a mucociliary clearance assay. Epithelial defense mechanisms, including basal cell mobilization and interferon-lambda induction, ramp up only after the initiation of cilia damage. Analysis of SARS-CoV-2 infection in Syrian hamsters further demonstrates the loss of motile cilia in vivo. This study identifies cilia damage as a pathogenic mechanism that could facilitate SARS-CoV-2 spread to the deeper lung parenchyma.
Throughout the history of mathematics, concepts of number and space have been tightly intertwined. We tested the hypothesis that cortical circuits for spatial attention contribute to mental ...arithmetic in humans. We trained a multivariate classifier algorithm to infer the direction of an eye movement, left or right, from the brain activation measured in the posterior parietal cortex. Without further training, the classifier then generalized to an arithmetic task. Its left versus right classification could be used to sort out subtraction versus addition trials, whether performed with symbols or with sets of dots. These findings are consistent with the suggestion that mental arithmetic co-opts parietal circuitry associated with spatial coding.
To compare the long-term outcomes of deep anterior lamellar keratoplasty (DALK) with penetrating keratoplasty (PK) in keratoconus.
Retrospective comparative case series (228 DALKs and 274 PKs). A ...biphasic linear model was used to describe the postoperative outcome of the endothelial cell density (ECD). Visual acuity, specular microscopy, corneal topography and optical coherence tomography findings were recorded.
Graft survival of the 502 keratoconus eyes was 96.7 at 10 years and 95.6% at 20 years. Visual acuity improved from 20/378±5.1 lines preoperatively to 20/32±2.1 lines at 30 months. The corneal ECD decreased from 2494±382 cells/mm
to 1521±659 cells/mm
at 10 years. The mean simulated keratometry increased from 44.88±2.54 D at 1 year to 46.60±3.0 D at 3 years. The mean follow-up was 103.4 months for DALKs and 106.1 months for PKs. The cumulated incidence of postoperative ocular hypertension requiring treatment was significantly higher in PKs than in DALKs. The early- and late-phase rates of ECD loss were significantly lower in DALKs than in PKs. These figures in DALKs were 50% of those observed in PKs. The simulated mean keratometry was significantly higher in DALKs than in PKs in the mid but not in the long term. No significant differences in visual acuity were observed between both groups. Manual dissection-DALK featured slower visual recovery than PK and big bubble-DALK, whereas big bubble-DALK and PK featured similar visual recovery.
DALK featuring higher endothelial survival and lower risk of postoperative ocular hypertension may be superior to PK when indicated for keratoconus.
Sound analysis by the cochlea relies on frequency tuning of mechanosensory hair cells along a tonotopic axis. To clarify the underlying biophysical mechanism, we have investigated the micromechanical ...properties of the hair cell's mechanoreceptive hair bundle within the apical half of the rat cochlea. We studied both inner and outer hair cells, which send nervous signals to the brain and amplify cochlear vibrations, respectively. We find that tonotopy is associated with gradients of stiffness and resting mechanical tension, with steeper gradients for outer hair cells, emphasizing the division of labor between the two hair-cell types. We demonstrate that tension in the tip links that convey force to the mechano-electrical transduction channels increases at reduced Ca
. Finally, we reveal gradients in stiffness and tension at the level of a single tip link. We conclude that mechanical gradients of the tip-link complex may help specify the characteristic frequency of the hair cell.
Purpose
This paper aims to explore the impact of team psychological safety and team learning on the creation of team knowledge. When teams engage in learning, their interactions contribute to ...improved performance. Very little research evaluates whether the learning also creates new knowledge related to the task or the team itself.
Design/methodology/approach
The proposed model is evaluated through a mixed method research design around a team problem-solving experiment. Task- and team-related team mental models are elicited using concept mapping and questionnaires and are measured before and after the experiment. The model is evaluated in engineering teams from the USA and France.
Findings
The findings confirm the proposed model; team psychological safety and team learning positively impact team knowledge creation for both task- and team-related knowledge.
Originality/value
This research has theoretical, methodological and practical implications. The team psychological safety model is expanded, team learning is evaluated from the team interactions instead of members’ self-assessments and team knowledge is measured dynamically. Developing team psychological safety and creating team learning opportunities positively impacts the team’s knowledge.
According to economic theories, preference for one item over others reveals its rank value on a common scale. Previous studies identified brain regions encoding such values. Here we verify that these ...regions can valuate various categories of objects and further test whether they still express preferences when attention is diverted to another task. During functional neuroimaging, participants rated either the pleasantness (explicit task) or the age (distractive task) of pictures from different categories (face, house, and painting). After scanning, the same pictures were presented in pairs, and subjects had to choose the one they preferred. We isolated brain regions that reflect both values (pleasantness ratings) and preferences (binary choices). Preferences were encoded whatever the stimulus (face, house, or painting) and task (explicit or distractive). These regions may therefore constitute a brain system that automatically engages in valuating the various components of our environment so as to influence our future choices.
L'analyse complexe, qui melange topologie, calcul differentiel, integration et meme algebre, est un sujet incontournable dont les applications traversent quasiment tous les domaines mathematiques.Cet ...ouvrage aborde les grands theoremes fondamentaux de l'analyse complexe en proposant un cours de base solide, sans delaisser les applications pratiques comme le calcul d'integrales ou l'etude des fonctions speciales. Les cinq premiers chapitres correspondent a un cours de niveau L3 sur les fonctions holomorphes, et contiennent strictement le programme de l'agregation de mathematiques en ce qui concerne l'analyse complexe. Les chapitres suivants correspondent plus specifiquement aux enseignements de M1 et de M2 (fonctions harmoniques, fonctions classiques, integration des formes differentielles, noyau de Bergman, theoremes de Runge, theoremes de Picard, theoremes de factorisation, etc.).Le cours est accompagne de nombreux exercices dont les corriges sont telechargeables sur dunod.com.
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