Pattern selection in growing tubular tissues

International audienceTubular organs display a wide variety of surface morphologies including circumferential and longitudinal folds, square and hexagonal undulations, and finger-type protrusions. Surface morphology is closely correlated to tissue function and serves as a clinical indicator for physiological and pathological conditions, but the regulators of surface morphology remain poorly understood. Here, we explore the role of geometry and elasticity on the formation of surface patterns. We establish morphological phase diagrams for patterns selection and show that increasing the thickness or stiffness ratio between the outer and inner tubular layers induces a gradual transition from circumferential to longitudinal folding. Our results suggest that physical forces act as regulators during organogenesis and give rise to the characteristic circular folds in the esophagus, the longitudinal folds in the valves of Kerckring, the surface networks in villi, and the crypts in the large intestine

The FIT-pull Method: an experimental tool to monitor the track measurements and the B proper time.

In this note we describe a statistical tool, the \textit{FIT-pull method}, that can test the reliability of the measurements of the tracks and the vertices on real and Monte-Carlo data without knowledge of the truth information. The basic mathematical formalism is derived from the Lagrange Multipliers method and briefly described. Several tests are performed to prove its validity in different situations. %KDifferent useful examples are discussed. In particular, by using Monte-Carlo simulation, we demonstrate that the method can be applied to check if the measured tracks or vertices have biases or incorrect covariance matrices. For correct input measurements we obtain pull distributions with a normal Gaussian statistical form. In this case the B proper time value and its error, which is a function of the track and vertex measurements, are correctly calculated. However, in the case of incorrect measurements, for example due to a systematic error or to a scale factor of the covariance matrix, the pull distributions studied deviate from normal Gaussians and the B proper time measurement can be affected. In principle the method can, if necessary, be used to recover information from corrupted measurements. Its potential in this capacity is demonstrated for the particular case of the decay channel $B^0_d \to \pi^+ \pi^-$ with the reconstructed Monte-Carlo data produced in 2004

A game theory model to explore the role of cooperation and diversity in community food security: the case of Southern Malawi

The Sustainable Development Goals aim at ending food insecurity by 2030. Therefore, civil society needs to understand the inherent complexities of both socio-economic and ecological dynamics and their interdependencies. In particular, the behavioural dynamics that underpin human agents are crucial in driving the final outcomes in terms of community food security and require further attention. Using household behaviour within a rural village of Southern Malawi as an example, we describe a game theory model representing cropping strategies: (1) cooperation, as driven by other-regarding preferences, and (2) conformation, the tendency to converge to similar crop planting choices as opposed to differentiation (and thus crop diversity). We find that the latter plays a crucial role in driving the system towards successful strategies: how individuals relate to social norms has greater effect. Cooperation is only necessary for community success when the community converges on crop planting choices. On the contrary, differentiation, the affirmation of the individual unique identity, can succeed with or without cooperation. We further elaborate on the idea that community level sustainability can be reached through different pathways, which might require food exchange mechanisms within and beyond the system boundaries. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature.This research is supported by the Basque Government through the BERC 2018-2021 program and by the Ikertzaile Doktoreentzako Hobekuntzarako doktoretza-ondoko Programa and by Spanish Ministry of Economy and Competitiveness MINECO through BC3 María de Maeztu excellence accreditation MDM-2017-0714 and by the Leverhulme TrustResearch Fellowship “CREATE: the network components of creativity and success. This work was also inspired and partially funded by the ASSETS (Attaining Sustainable Services from Ecosystems) project (NERC/ESPA NE-J002267-1)

Mathematical modelling of axonal cortex contractility

The axonal cortex is composed of a regular structure of F-actin and spectrin able to contract thanks to myosin II motors. Such an active tension is of fundamental importance in controlling the physiological shape of axons. Recent experiments show that axons modulate the contraction of the cortex when subject to mechanical deformations, exhibiting a non-trivial coupling between the hoop and the axial active tension. However, the underlying mechanisms are still poorly understood. In this paper, we propose a continuum model of the axon based on the active strain theory. By using the Coleman–Noll procedure, we shed light on the coupling between the hoop and the axial active strain through the Mandel stress tensor. We propose a qualitative analysis of the system under the simplifying assumption of incompressibility, showing the existence of a stable equilibrium solution. In particular, our results show that the axon regulates the active contraction to maintain a homeostatic stress state. Finally, we propose numerical simulations of the model, using a more suitable compressible constitutive law. The results are compared with experimental data, showing an excellent quantitative agreement

Guided-wave photodetectors in germanium on optical chips in silicon-on-insulator

We report the integration of near-infrared waveguide photodetectors in polycrystalline Germanium with Silicon on Insulator optical chips for power monitor applications. We discuss design and fabrication of the devices as well as their characterization in terms of dark current, responsivity and signal to noise ratio

Diffuse Lipomatosis of Thyroid Gland

n/

ISW effect in Unified Dark Matter Scalar Field Cosmologies: an analytical approach

We perform an analytical study of the Integrated Sachs-Wolfe (ISW) effect within the framework of Unified Dark Matter models based on a scalar field which aim at a unified description of dark energy and dark matter. Computing the temperature power spectrum of the Cosmic Microwave Background anisotropies we are able to isolate those contributions that can potentially lead to strong deviations from the usual ISW effect occurring in a $\Lambda$CDM universe. This helps to highlight the crucial role played by the sound speed in the Unified Dark Matter models. Our treatment is completely general in that all the results depend only on the speed of sound of the dark component and thus it can be applied to a variety of unified models, including those which are not described by a scalar field but relies on a single dark fluid.Comment: 15 pages, LateX file; one comment after Eq.(36) and formula (44) added in order to underline procedure and main results. Accepted for publication in JCAP; some typos correcte

Self-organisation and psychotherapy

Neste artigo, resultado de uma pesquisa de tipo qualitativo, hermenêutico e documental, procuramos mostrar como as Ciências Cognitivas, desde a sua constituição, têm contribuído para a compreensão do ser humano. Fazemos referência às visões mais racionalistas da mente, que a entendem semelhante a um sistema computacional, até à visão menos (não) racionalista que lhe confere valor cognitivo, envolta em emoções e afetos, que numa visão mais construtivista – ou pós-racionalista – se diria que traduz significados, traduz uma vivência ou uma história narrativa (e) pessoal. Assim, apresentamos o modelo de terapia cognitiva pós-racionalista de Vittorio Guidano, refletindo sobre os fundamentos epistemológicos do Movimento da Auto-organização (MAO), nos quais ele se fundamenta. Descrevemos sumariamente os alicerces epistemológicos do MAO, os quais garantem a este modelo uma dimensão holista e explicativa do processo de construção da identidade humana, que pode ser descrita como processo de conhecimento, capaz de vivenciar e ao mesmo tempo perceber e avaliar a sua própria experiência (autoconsciência). O ser humano age na intersubjetividade, num mundo pluralista, com os seus congéneres, partilhando experiências e interpretando ações (complexificando-se através desses acoplamentos). Pretendemos, também, ilustrar que a matriz de funcionamento interno de cada ser humano, a qual lhe permite ordenar essa múltipla e facetada realidade, assim como formar/construir/ordenar significados pessoais, é o vínculo emotivo-afetivo.In this paper, which is the result of a qualitative, hermeneutical and documental research, we intend to show how the Cognitive Sciences, since their beginning, have contributed to the understanding of human beings. We refer to the rationalistic understanding of the mind (the mind is like a computer system), and also to the non-rationalistic understanding, which attributes to the mind a cognitive value, immersed in emotions and affections. In addition, according to a constructivist or post-rationalistic understanding, the mind translates meanings, an experience or a personal narrative story. Thus, we present the model of post-rationalistic cognitive therapy of Vittorio Guidano, reflecting on the epistemological foundations of the Self-Organization Movement, on which it is based. We describe briefly the epistemological principles of the Self-Organization Movement, which give to this model a holistic and explanatory dimension of the process of construction of human identity. This identity can be described as the human beings’ process of self-knowledge, as we are capable of experiencing and at the same time perceiving and evaluating, our own experiences (self-consciousness). The human being acts on intersubjectivity, in a pluralistic world with his peers, sharing experiences and interpreting actions. We also want to illustrate that the matrix of inner functioning of every human being, which allows us to sort this multi-faceted reality in a single personal order, is the emotional bond.(undefined

Smoking-related lung diseases: a clinical perspective

n/

A 13-Gene DNA Methylation Analysis Using Oral Brushing Specimens as an Indicator of Oral Cancer Risk: A Descriptive Case Report

Analysis of genetic or epigenetic markers from saliva or brushing specimens has been proposed as a diagnostic aid to identify patients at risk of developing oral cancer. However, no reliable non-invasive molecular method for this purpose is commercially available. In the present report, we describe the potential application of a procedure based on a 13-gene DNA methylation analysis using oral brushing samples from a patient affected by oral leukoplakia who developed two metachronous oral carcinomas during the follow-up period. A positive or a negative score was calculated for each brushing sample based on a predefined cut-off value. In this patient, a positive score was detected in the oral leukoplakia diagnosed more than 2 years before the development of oral squamous cell carcinoma and subsequently in clinically healthy mucosa 8 months before the appearance of a secondary tumor. This suggests a potential role of our procedure as an indicator of oral cancer risk