Rocket engine analog simulation

Mathematical equations simulate the operation of a rocket engine, simulate destructive and nondestructive tests to verify engine design feasibility, and investigate nonlinear variations in engine performance

Tourist or Traveler? Unpacking Informal Conversations between Teachers and Young Children across Diversity

The world is in the midst of a dramatic demographic shift: culturally, ethnically, and socioeconomically. To address the needs of an increasingly diverse student population, research has examined the effects of teacher-student relationships. This chapter describes a study that used autophotography to examine the ways teachers engage in informal conversations with young children who come from different racial, ethnic, and socioeconomic backgrounds, around the child’s own photos of home. Specifically, conversations were interrogated to identify what impacts the teacher-student interactions across differences. Using Gee’s discourse analysis, this study explored how the teachers built or lessened what the children viewed as significant, how they distributed their social goods—influence, power, or status—and how they created or positioned identities within the conversations. The findings inform the mission of enhancing teacher-student relationships and content relevance through providing new insights into how teachers and young children interact, connect, and change within their conversations

Towards Uncovering Feature Extraction from Temporal Signals in Deep CNN: The ECG Case Study

Despite all the progress made in biomedical field, the Electrocardiogram (ECG) is still one of the most commonly used signal in medical examinations. Over the years, the problem of ECG classification has been approached in many different ways, most of which rely on the extraction of features from the signal in the form of temporal or morphological characteristics. Although feature engineering can led to adequately good results, it mostly relies on human ability and experience in selecting the correct feature set. In the last decade, a growing class of techniques based on Convolutional Neural Network (CNN) has been proposed in opposition to feature engineering. The efficiency and accuracy of CNN-based approaches is indisputable, however their ability in extracting and using temporal features from raw signal is poorly understood. The main objective of this work was to uncover the differences and the relationships between CNN feature maps and human-curated temporal features, towards a deeper understanding of neural-based approaches for ECG. In fact, the proposed study succeeded in finding a similarity between the output stage of the first layers of a deep 1D-CNN with several temporal features, demonstrating that not only that the engineered features effectively works in ECG classification tasks, but also that CNN can improve those features by elaborating them towards an higher level of abstraction

Lactococcal 949 group phages recognize a carbohydrate receptor on the host cell surface

Lactococcal bacteriophages represent one of the leading causes of dairy fermentation failure and product inconsistencies. A new member of the lactococcal 949 phage group, named WRP3, was isolated from cheese whey from a Sicilian factory in 2011. The genome sequence of this phage was determined, and it constitutes the largest lactococcal phage genome currently known, at 130,008 bp. Detailed bioinformatic analysis of the genomic region encoding the presumed initiator complex and baseplate of WRP3 has aided in the functional assignment of several open reading frames (ORFs), particularly that for the receptor binding protein required for host recognition. Furthermore, we demonstrate that the 949 phages target cell wall phospho-polysaccharides as their receptors, accounting for the specificity of the interactions of these phages with their lactococcal hosts. Such information may ultimately aid in the identification of strains/strain blends that do not present the necessary saccharidic target for infection by these problematic phages

Rac inhibits thrombin-induced Rho activation: evidence of a Pak-dependent GTPase crosstalk

The strict spatio-temporal control of Rho GTPases is critical for many cellular functions, including cell motility, contractility, and growth. In this regard, the prototypical Rho family GTPases, Rho, Rac, and Cdc42 regulate the activity of each other by a still poorly understood mechanism. Indeed, we found that constitutively active forms of Rac inhibit stress fiber formation and Rho stimulation by thrombin. Surprisingly, a mutant of Rac that is unable to activate Pak1 failed to inhibit thrombin signaling to Rho. To explore the underlying mechanism, we investigated whether Pak1 could regulate guanine nucleotide exchange factors (GEFs) for Rho. We found that Pak1 associates with P115-RhoGEF but not with PDZ-RhoGEF or LARG, and knock down experiments revealed that P115-RhoGEF plays a major role in signaling from thrombin receptors to Rho in HEK293T cells. Pak1 binds the DH-PH domain of P115-RhoGEF, thus suggesting a mechanism by which Rac stimulation of Pak1 may disrupt receptor-dependent Rho signaling. In agreement, expression of a dominant-negative Pak-Inhibitory Domain potentiated the activation of Rho by thrombin, and prevented the inhibition of Rho by Rac. These findings indicate that Rac interferes with receptor-dependent Rho stimulation through Pak1, thus providing a mechanism for cross-talk between these two small-GTPases

A Combined Experimental and Theoretical Study of Photodouble Ionization of Water at 32 eV Excess Energy and Unequal Energy Sharing

In this paper we present a part of our investigation of the photodouble ionization (PDI) of gaseous water. Synchrotron radiation from ELETTRA storage ring was used to ionize the water molecule, and the two emitted electrons were collected in coincidence after angle and energy selection. We have compared the measured dication states with those known from literature and showed the angular distributions of the two photoelectrons measured for the first time, for different excess energies and under different energy sharing conditions. A detailed comparison with theoretical calculations is given to help understand some details of the PDI mechanism.Fil: Penson, Conner. Embry-riddle Aeronautical University; Estados UnidosFil: Turri, Giorgio. Full Sail University; Estados UnidosFil: Avaldi, Lorenzo. Consiglio Nazionale delle Ricerche; ItaliaFil: Randazzo, Juan Martin. Comisión Nacional de Energí­a Atómica. Gerencia del Area Investigación y Aplicaciones No Nucleares. Gerencia de Física (Centro Atómico Balseiro). División Colisiones Atómicas; Argentina. University of Central Florida; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; ArgentinaFil: Ancarani, Lorenzo Ugo. Université de Lorraine; FranciaFil: Bolognesi, Paola. Consiglio Nazionale delle Ricerche; Itali

Photo-double-ionization of water at 20 eV above threshold

The photodouble ionization of the water molecule is studied at 20 eV excess energy in a combined experimental and theoretical investigation. In the experiments, two photoelectrons of equal kinetic energy are detected in coincidence after energy and angular selection. On the theoretical side, a generalized Sturmian function approach is implemented to describe accurately the correlated two-electron continuum, while separable products of Moccia orbitals [J. Chem. Phys. 40, 2164 (1964)JCPSA60021-960610.1063/1.1725489] are used for the initial electronic state of the water molecule. The theoretical triple-differential cross sections (TDCSs) are averaged over all possible molecular orientations in order to be compared with the experiments. The measured TDCSs display rich angular distributions that are in large part well reproduced by the adopted first-order treatment of the interaction with a two-active-electron target.Fil: Randazzo, Juan Martin. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; ArgentinaFil: Turri, G.. Embry-riddle Aeronautical University, Physical Sciences; Estados UnidosFil: Bolognesi, P.. CNR-Istituto di Struttura della Materia; ItaliaFil: Mathis, J.. Embry-riddle Aeronautical University, Physical Sciences; Estados UnidosFil: Ancarani, L. U.. Université de Lorraine; FranciaFil: Avaldi, L.. CNR-Istituto di Struttura della Materia; Itali

Observations and predictions at CesrTA, and outlook for ILC

In this paper, we will describe some of the recent experimental measurements [1, 2, 3] performed at CESRTA [4], and the supporting simulations, which probe the interaction of the electron cloud with the stored beam. These experiments have been done over a wide range of beam energies, emittances, bunch currents, and fill patterns, to gather sufficient information to be able to fully characterize the beam-electron-cloud interaction and validate the simulation programs. The range of beam conditions is chosen to be as close as possible to those of the ILC damping ring, so that the validated simulation programs can be used to predict the performance of these rings with regard to electroncloud- related phenomena. Using the new simulation code Synrad3D to simulate the synchrotron radiation environment, a vacuum chamber design has been developed for the ILC damping ring which achieves the required level of photoelectron suppression. To determine the expected electron cloud density in the ring, EC buildup simulations have been done based on the simulated radiation environment and on the expected performance of the ILC damping ring chamber mitigation prescriptions. The expected density has been compared with analytical estimates of the instability threshold, to verify that the ILC damping ring vacuum chamber design is adequate to suppress the electron cloud single-bunch head-tail instability.Comment: 11 pages, contribution to the Joint INFN-CERN-EuCARD-AccNet Workshop on Electron-Cloud Effects: ECLOUD'12; 5-9 Jun 2012, La Biodola, Isola d'Elba, Ital