PCNS: A novel protocadherin required for cranial neural crest migration and somite morphogenesis in Xenopus

AbstractProtocadherins (Pcdhs), a major subfamily of cadherins, play an important role in specific intercellular interactions in development. These molecules are characterized by their unique extracellular domain (EC) with more than 5 cadherin-like repeats, a transmembrane domain (TM) and a variable cytoplasmic domain. PCNS (Protocadherin in Neural crest and Somites), a novel Pcdh in Xenopus, is initially expressed in the mesoderm during gastrulation, followed by expression in the cranial neural crest (CNC) and somites. PCNS has 65% amino acid identity to Xenopus paraxial protocadherin (PAPC) and 42–49% amino acid identity to Pcdh 8 in human, mouse, and zebrafish genomes. Overexpression of PCNS resulted in gastrulation failure but conferred little if any specific adhesion on ectodermal cells. Loss of function accomplished independently with two non-overlapping antisense morpholino oligonucleotides resulted in failure of CNC migration, leading to severe defects in the craniofacial skeleton. Somites and axial muscles also failed to undergo normal morphogenesis in these embryos. Thus, PCNS has essential functions in these two important developmental processes in Xenopus

Annual Report of the Town of Monson Maine by the Municipal Officers including Report of Superintendent of Schools for the Municipal Year 1930-1931

Original scanned reports courtesy of Monson Historical Societ

ISLES 2015 - A public evaluation benchmark for ischemic stroke lesion segmentation from multispectral MRI

Ischemic stroke is the most common cerebrovascular disease, and its diagnosis, treatment, and study relies on non-invasive imaging. Algorithms for stroke lesion segmentation from magnetic resonance imaging (MRI) volumes are intensely researched, but the reported results are largely incomparable due to different datasets and evaluation schemes. We approached this urgent problem of comparability with the Ischemic Stroke Lesion Segmentation (ISLES) challenge organized in conjunction with the MICCAI 2015 conference. In this paper we propose a common evaluation framework, describe the publicly available datasets, and present the results of the two sub-challenges: Sub-Acute Stroke Lesion Segmentation (SISS) and Stroke Perfusion Estimation (SPES). A total of 16 research groups participated with a wide range of state-of-the-art automatic segmentation algorithms. A thorough analysis of the obtained data enables a critical evaluation of the current state-of-the-art, recommendations for further developments, and the identification of remaining challenges. The segmentation of acute perfusion lesions addressed in SPES was found to be feasible. However, algorithms applied to sub-acute lesion segmentation in SISS still lack accuracy. Overall, no algorithmic characteristic of any method was found to perform superior to the others. Instead, the characteristics of stroke lesion appearances, their evolution, and the observed challenges should be studied in detail. The annotated ISLES image datasets continue to be publicly available through an online evaluation system to serve as an ongoing benchmarking resource (www.isles-challenge.org).Peer reviewe

Dynamic moment invariants for nonlinear Hamiltonian systems

Distributions of particles being transported through a nonlinear Hamiltonian system are studied. Using normal form techniques, a procedure to obtain invariant functions of moments of the distribution is given. These functions are invariant for the given Hamiltonian system and are called dynamic moment invariants. These techniques are used to obtain dynamic moment invariants for the nonlinear pendulum Hamiltonian system

Expression for a general element of an SO(n) matrix

We derive the expression for a general element of an SO(n) matrix. All elements are obtained from a single element of the matrix. This has applications in recently developed methods for computing Lyapunov exponents

Dynamic moment invariants for nonlinear Hamiltonian systems

Distributions of particles being transported through a nonlinear Hamiltonian system are studied. Using normal form techniques, a procedure to obtain invariant functions of moments of the distribution is given. These functions are invariant for the given Hamiltonian system and are called dynamic moment invariants. These techniques are used to obtain dynamic moment invariants for the nonlinear pendulum Hamiltonian system

© Hindawi Publishing Corp. EXPRESSION FOR A GENERAL ELEMENT OF AN SO(n) MATRIX

We derive the expression for a general element of an SO(n) matrix. All elements are obtained from a single element of the matrix. This has applications in recently developed methods for computing Lyapunov exponents. 2000 Mathematics Subject Classification: 22E70, 20G05

Computation of the Lyapunov spectrum for continuous-time dynamical systems and discrete maps

In this paper, we describe in detail a method of computing Lyapunov exponents for a continuous-time dynamical system and extend the method to discrete maps. Using this method, a partial Lyapunov spectrum can be computed using fewer equations as compared to the computation of the full spectrum, there is no difficulty in evaluating degenerate Lyapunov spectra, the equations are straightforward to generalize to higher dimensions, and the minimal set of dynamical variables is used. Explicit proofs and other details not given in previous work are included here. [S1063-651X(99)07212-8]

Computation of the Lyapunov spectrum for continuous-time dynamical systems and discrete maps

In this paper, we describe in detail a method of computing Lyapunov exponents for a continuous-time dynamical system and extend the method to discrete maps. Using this method, a partial Lyapunov spectrum can be computed using fewer equations as compared to the computation of the full spectrum, there is no difficulty in evaluating degenerate Lyapunov spectra, the equations are straightforward to generalize to higher dimensions, and the minimal set of dynamical variables is used. Explicit proofs and other details not given in previous work are included here