Regional requirements for Dishevelled signaling during Xenopus gastrulation: separable effects on blastopore closure, mesendoderm internalization and archenteron formation

During amphibian gastrulation, the embryo is transformed by the combined actions of several different tissues. Paradoxically, many of these morphogenetic processes can occur autonomously in tissue explants, yet the tissues in intact embryos must interact and be coordinated with one another in order to accomplish the major goals of gastrulation: closure of the blastopore to bring the endoderm and mesoderm fully inside the ectoderm, and generation of the archenteron. Here, we present high-resolution 3D digital datasets of frog gastrulae, and morphometrics that allow simultaneous assessment of the progress of convergent extension, blastopore closure and archenteron formation in a single embryo. To examine how the diverse morphogenetic engines work together to accomplish gastrulation, we combined these tools with time-lapse analysis of gastrulation, and examined both wild-type embryos and embryos in which gastrulation was disrupted by the manipulation of Dishevelled (Xdsh) signaling. Remarkably, although inhibition of Xdsh signaling disrupted both convergent extension and blastopore closure, mesendoderm internalization proceeded very effectively in these embryos. In addition, much of archenteron elongation was found to be independent of Xdsh signaling, especially during the second half of gastrulation. Finally, even in normal embryos, we found a surprising degree of dissociability between the various morphogenetic processes that occur during gastrulation. Together, these data highlight the central role of PCP signaling in governing distinct events of Xenopus gastrulation, and suggest that the loose relationship between morphogenetic processes may have facilitated the evolution of the wide variety of gastrulation mechanisms seen in different amphibian species

Determination of plastic properties of metals by instrumented indentation using a stochastic optimization algorithm

A novel optimization approach, capable of extracting the mechanical properties of an elasto-plastic material from indentation data, is proposed. Theoretical verification is performed on two simulated configurations. The first is based on the analysis of the load-displacement data and the topography of the residual imprint of a single conical indenter. The second is based on the load-displacement data obtained from two conical indenters with different semi-angles. In both cases, a semi-analytical approach [e.g., Dao et al., Acta Mater. 49, 3899 (2001) and Bucaille et al., Acta Mater. 51, 1663 (2003)] is used to estimate Young's modulus, yield stress, and strain hardening coefficient from the load-displacement data. An inverse finite element model, based on a commercial solver and a newly developed optimization algorithm based on a robust stochastic methodology, uses these approximate values as starting values to identify parameters with high accuracy. Both configurations use multiple data sets to extract the elastic-plastic material properties; this allows the mechanical properties of materials to be determined in a robust wa

Weitere Parallelen in Tocharisch B zur altuigurischen Daśakarmapathāvadānamālā: Mahendrasena- und Ṣaḍdanta-Avadāna

Descriptive and Comparative Linguistic

Construction of the New Prototype of Main Quadrupole Cold Masses for the Arc Short Straight Sections of LHC

Each cold mass of the short straight sections in the eight LHC arcs will contain a 3.25 m long twin aperture quadrupole of a nominal gradient of 223 T/m. This magnet will be aligned in a 5.3 m long inertia tube together with auxiliary magnets on each end. On the quadrupole connection end either a pair of 38 cm long octupole or trim quadrupole magnets will be mounted, on the other end there will be combined sextupole-dipole correctors with a yoke length of 1.26 m. The powering of the main quadrupoles will be assured by two pairs of copper stabilized superconducting bus-bars placed inside the cold mass next to the bus-bars for the main dipole magnets. Each of the two quadrupole apertures will be connected to its quench protection diode. The construction of three prototypes has been entrusted to the CEA/Saclay laboratory, in the frame of the special French contribution to the LHC project. The first cold mass prototype has been completed and warm-measured for its multipole content at CEA. The second cold mass is presently under completion. The paper will review the experience with the development of the quadrupole coils and cold mass construction and gives the results of the first warm magnetic measurements. An outlook for the series manufacture of the 400 arc quadrupole magnets and their cold masses for the LHC machine will complete the report

Status of the Cold Mass of the Short Straight Section for the LHC

In the framework of the LHC (Large Hadron Collider) R&D program, CERN and CEA-Saclay have collaborated to develop and construct two quadrupole magnet prototypes which have been successfully cold-teste d. This collaboration has been extended as part of French special contribution to the LHC project. The previous design has been adapted to meet the new LHC parameters and two new cold masses are being constructed. This paper describes the new cold masses, their assembly process and the foreseen organization for the industrial production of about 470 units

Elaboration and TEM structural study of interfaces in composites produced by precipitation

Model ceramic matrix composites have been manufactured in a wide range of materials using the precipitation of a metal (Cu, Ni, Cr) in a ceramic matrix (nitride AIN or oxides MgO, Al2O3) providing, in each case low energy configurations at the heterophase interfaces. In connection to microelectronic applications, copper metallic particles precipitate in AIN after implantation by copper ions and anneal of the ceramic matrix. Faceted particles are imaged by HRTEM and are associated to a low energy structural and chemical configuration. Internal reduction experiments have been carried out on (Mg,Ni)O, (Mg,Cu)O and (Al,Cr)2O3 mixed oxides; the morphology, chemical composition and orientation relationship of the different precipitates are obtained through TEM observations and discussed in terms of interfacial energy and precipitate growth mechanism and kinetics. Conventional and high resolution TEM in conjonction to structural models have allowed a comprehensive description of the interface

Motivation: key to a healthy lifestyle in people with diabetes? Current and emerging knowledge and applications

Aim Motivation to take up and maintain a healthy lifestyle is key to diabetes prevention and management. Motivations are driven by factors on the psychological, biological and environmental levels, which have each been studied extensively in various lines of research over the past 25 years. Here, we analyse and reflect on current and emerging knowledge on motivation in relation to lifestyle behaviours, with a focus on people with diabetes or obesity. Structured according to psychological, (neuro‐)biological and broader environmental levels, we provide a scoping review of the literature and highlight frameworks used to structure motivational concepts. Results are then put in perspective of applicability in (clinical) practice. Results Over the past 25 years, research focusing on motivation has grown exponentially. Social–cognitive and self‐determination theories have driven research on the key motivational concepts ‘self‐efficacy’ and ‘self‐determination’. Neuro‐cognitive research has provided insights in the processes that are involved across various layers of a complex cortical network of motivation, reward and cognitive control. On an environmental – more upstream – level, motivations are influenced by characteristics in the built, social, economic and policy environments at various scales, which have provided entry points for environmental approaches influencing behaviour. Conclusions Current evidence shows that motivation is strongly related to a person's self‐efficacy and capability to initiate and maintain healthy choices, and to a health climate that supports autonomous choices. Some approaches targeting motivations have been shown to be promising, but more research is warranted to sustainably reduce the burden of diabetes in individuals and populations

Welfare Plastic: The Transformation of Public Assistance in the Electronic Age

Several states have developed electronic benefit transfer (EBT) systems to deliver cash assistance and food stamp benefits. These systems establish electronic account balances which recipients access through the use of a debit card at terminals such as bank automatic teller machines or transaction authorization machines like those that validate credit card charges. We examine the potential effects of such systems on involved stakeholders, including government agencies, benefit recipients, financial institutions, and food retailers. Overall, each stakeholder group benefits from EBT, but some subgroups do not fare as well. Several key issues are identified