A ring in a shell: the large-scale 6D structure of the Vela OB2 complex

The Vela OB2 association is a group of 10 Myr stars exhibiting a complex spatial and kinematic substructure. The all-sky Gaia DR2 catalogue contains proper motions, parallaxes (a proxy for distance) and photometry that allow us to separate the various components of Vela OB2. We characterise the distribution of the Vela OB2 stars on a large spatial scale, and study its internal kinematics and dynamic history. We make use of Gaia DR2 astrometry and published Gaia-ESO Survey data. We apply an unsupervised classification algorithm to determine groups of stars with common proper motions and parallaxes. We find that the association is made up of a number of small groups, with a total current mass over 2330 Msun. The three-dimensional distribution of these young stars trace the edge of the gas and dust structure known as the IRAS Vela Shell across 180 pc and shows clear signs of expansion. We propose a common history for Vela OB2 and the IRAS Vela Shell. The event that caused the expansion of the shell happened before the Vela OB2 stars formed, imprinted the expansion in the gas the stars formed from, and most likely triggered star formation.Comment: Accepted by A&A (02 November 2018), 13 pages, 9+2 figure

Challenges and strategies in precision medicine for non-small cell lung cancer

Lung cancer is the most common cause of cancer- related death worldwide, causing over 1.2 million deaths each year. Non–small-cell lung cancer (NSCLC) consists of a group of malignancies that are pathologically and molecularly diverse but that are all characterised by a poor prognosis. Survival rates for lung cancer patients have improved very slowly and only to a modest degree owing partly to poor funding for research into this malignancy and stigma associated with smoking, as well as relative chemo-resistance. However, in recent years, NSCLC has become an exemplar for precision medicine, mainly following development of drugs targeting the receptors of epidermal growth factor and anaplastic lymphoma kinase. While epidermal growth factor receptor and anaplastic lymphoma kinase inhibitors are only applicable to a minority of patients and benefits are almost invariably short-lived, current studies indicate that at least 50% of patients with NSCLC have a targetable mutation. With a growing armamentarium of inhibitors against these targets in development, there is a hope that a greater proportion of patients will benefit from precision medicine and that such benefits will be sustained. However, there remain significant challenges in the development of precision medicine in NSCLC. These include: identification and validation of new targets; ensuring biopsies are fit for purpose; tumour heterogeneity; requirements for serial tumour assessments; and not least cost. In this review, we will discuss the current status of precision medicine in NSCLC as well as how basic and translational research are paving the way towards overcoming the above challenges. In addition, we will pay attention to clinical strategies in respect to liquid biopsies and the potential use of extracellular vesicles such as exosomes in cancer therapeutics

Propulsion simulator for magnetically-suspended wind tunnel models

The objective of phase two of a current investigation sponsored by NASA Langley Research Center is to demonstrate the measurement of aerodynamic forces/moments, including the effects of exhaust gases, in magnetic suspension and balance system (MSBS) wind tunnels. Two propulsion simulator models are being developed: a small-scale and a large-scale unit, both employing compressed, liquified carbon dioxide as propellant. The small-scale unit was designed, fabricated, and statically-tested at Physical Sciences Inc. (PSI). The large-scale simulator is currently in the preliminary design stage. The small-scale simulator design/development is presented, and the data from its static firing on a thrust stand are discussed. The analysis of this data provides important information for the design of the large-scale unit. A description of the preliminary design of the device is also presented

The Seigniory of Sark and the Duchy Of Cornwall: Similarities and Differences Including Observations on the Isles of Scilly

A unified and robust mathematical model for compressible and incompressible linear elasticity can be obtained by rephrasing the Herrmann formulation within the Hellinger-Reissner principle. This quasi-optimally converging extension of PEERS (Plane Elasticity Element with Reduced Symmetry) is called Dual-Mixed Hybrid formulation (DMH). Explicit residual-based a posteriori error estimates for DMH are introduced and are mathematically shown to be locking-free, reliable, and efficient. The estimator serves as a refinement indicator in an adaptive algorithm for effective automatic mesh generation. Numerical evidence supports that the adaptive scheme leads to optimal convergence for Lam\ue9 and Stokes benchmark problems with singularities

Finite element solution of free‐surface ship‐wave problems

An unstructured finite element solver to evaluate the ship‐wave problem is presented. The scheme uses a non‐structured finite element algorithm for the Euler or Navier–Stokes flow as for the free‐surface boundary problem. The incompressible flow equations are solved via a fractional step method whereas the non‐linear free‐surface equation is solved via a reference surface which allows fixed and moving meshes. A new non‐structured stabilized approximation is used to eliminate spurious numerical oscillations of the free surface

Attachment and mentalization efforts to promote creative learning in kindergarten through fifth grade elementary school students with broad extension to all grades and some organizations

The model described here – Creating a Peaceful School Learning Environment (CAPSLE) – uniquely applies mentalizing thinking combined with work on power and shame dynamics, to create an institutional climate where the student is better able to deal with bullying aggression and other critical psychodynamic climate factors

A Poroelastic Mixture Model of Mechanobiological Processes in Biomass Growth: Theory and Application to Tissue Engineering

In this article we propose a novel mathematical description of biomass growth that combines poroelastic theory of mixtures and cellular population models. The formulation, potentially applicable to general mechanobiological processes, is here used to study the engineered cultivation in bioreactors of articular chondrocytes, a process of Regenerative Medicine characterized by a complex interaction among spatial scales (from nanometers to centimeters), temporal scales (from seconds to weeks) and biophysical phenomena (fluid-controlled nutrient transport, delivery and consumption; mechanical deformation of a multiphase porous medium). The principal contribution of this research is the inclusion of the concept of cellular \u201cforce isotropy\u201d as one of the main factors influencing cellular activity. In this description, the induced cytoskeletal tensional states trigger signalling transduction cascades regulating functional cell behavior. This mechanims is modeled by a parameter which estimates the influence of local force isotropy by the norm of the deviatoric part of the total stress tensor. According to the value of the estimator, isotropic mechanical conditions are assumed to be the promoting factor of extracellular matrix production whereas anisotropic conditions are assumed to promote cell proliferation. The resulting mathematical formulation is a coupled system of nonlinear partial differential equations comprising: conservation laws for mass and linear momentum of the growing biomass; advection\u2013diffusion\u2013reaction laws for nutrient (oxygen) transport, delivery and consumption; and kinetic laws for cellular population dynamics. To develop a reliable computational tool for the simulation of the engineered tissue growth process the nonlinear differential problem is numerically solved by: (1) temporal semidiscretization; (2) linearization via a fixed-point map; and (3) finite element spatial approximation. The biophysical accuracy of the mechanobiological model is assessed in the analysis of a simplified 1D geometrical setting. Simulation results show that: (1) isotropic/anisotropic conditions are strongly influenced by both maximum cell specific growth rate and mechanical boundary conditions enforced at the interface between the biomass construct and the interstitial fluid; (2) experimentally measured features of cultivated articular chondrocytes, such as the early proliferation phase and the delayed extracellular matrix production, are well described by the computed spatial and temporal evolutions of cellular populations