Search results for "Ewing"
showing 10 items of 270 documents
Numerical simulations of the internal shock model in magnetized relativistic jets of blazars
2015
The internal shocks scenario in relativistic jets is used to explain the variability of the blazar emission. Recent studies have shown that the magnetic field significantly alters the shell collision dynamics, producing a variety of spectral energy distributions and light-curves patterns. However, the role played by magnetization in such emission processes is still not entirely understood. In this work we numerically solve the magnetohydodynamic evolution of the magnetized shells collision, and determine the influence of the magnetization on the observed radiation. Our procedure consists in systematically varying the shell Lorentz factor, relative velocity, and viewing angle. The calculatio…
Simulations of Precessing Jets
2003
We report on the results of a three-dimensional, relativistic, hydrodynamical simulation of a precessing jet through which a compact blob of matter is set to propagate. We conclude that the morphology of superluminal sources is the result of a complex combination of phase motions, viewing angle selection effects, and non-linear interactions between perturbations and the underlying jet and/or external medium.
Changes in the trajectory of the radio jet in 0735+178?
2001
We present multi-epoch 8.4 and 43 GHz Very Long Baseline Array images of the BL Lac object 0735+178. The images confirm the presence of a twisted jet with two sharp apparent bends of 90$^{\circ}$ within two milliarcseconds of the core, resembling a helix in projection. The observed twisted geometry could be the result of precession of the jet inlet, but is more likely produced by pressure gradients in the external medium through which the jet propagates. Quasi-stationary components are observed at the locations of the 90$^{\circ}$ bends, possibly produced by differential Doppler boosting. Identification of components across epochs, since the earliest VLBI observations of this source in 1979…
THE ACCELERATING JET OF 3C 279
2012
Analysis of the proper motions of the subparsec scale jet of the quasar 3C 279 at 15 GHz with the Very Long Baseline Array shows significant accelerations in four of nine superluminal features. Analysis of these motions is combined with the analysis of flux density light curves to constrain values of Lorentz factor and viewing angle (and their derivatives) for each component. The data for each of these components are consistent with significant changes to the Lorentz factor, viewing angle, and azimuthal angle, suggesting jet bending with changes in speed. We see that for these observed components Lorentz factors are in the range Γ = 10-41, viewing angles are in the range = 0.°1-5.°0, and in…
P–294 Mapping COVID–19 affected genes from blood in a Window of implantation co-expression network reveals a potentially compromised landscape
2021
Abstract Study question Could the transcriptomic and functional landscape of the window of implantation be compromised by SARS-COV–2 infection? Summary answer Some of the main genes and pathways involved in the window of implantation are affected in blood of COVID–19 patients and receptivity could be affected. What is known already There is a concern whether SARS-COV–2 can disrupt assisted reproduction treatments (ARTs) and fertility in short and long terms. In the endometrium, it was found that genes related to the viral infection (ACE2, TMPRSS2/4, CTSL/B) are involved in menstrual cycle progression, especially in the Window of Implantation (WOI). However, there are no studies describing t…
Doing Science: Peer reviewing
2014
External peer review is a hallmark of science. “Published in a peer-reviewed journal” is a sign of quality, meaning that the work has been scrutinised by knowledgeable and independent peers. Moreover, peer review also serves the purpose of improving the work after the authors have done their best and, thus, being a reviewer carries a responsibility. However, it comes with little reward; reviewing is usually done without financial compensation and often outside of work hours. But reviewing is rewarding in itself! Besides being pro bono , it exposes you, as a reviewer, to novel findings and adds a new perspective to your own research and scientific writing. And you can add “Peer reviewer for …
Contributions Regarding the Reduction of Production Costs for Brewing by Recovering and Reusing the Carbon Dioxide
2014
Abstract Nowadays in every field the main aim is to produce corresponding quality products at competitive prices for buyers. In addition to the multiple possibilities to reduce the brewing production cost, one of the most significant ways is to reduce the production cost by recovering the carbon dioxide (CO2) resulting from the fermentation of beer, taking into account the fact that the CO2 thus resulting is completely natural. This scientific paper presents a certain strategy based on costs, strategy which relies on the experience of the authors, on the economic impact of CO2 recovery resulting from the fermentation of beer and which reflects itself in the production cost and implicitly in…
Utility of social networks and online data collection in nursing research: Analysis of Spanish nurses’ level of knowledge about palliative care
2018
Introduction Internet-based social networks are used by nurses with different purposes, including the creation of working groups and to share and create knowledge. Purpose To evaluate the utility of social networks in the dissemination of an online questionnaire and to measure Spanish RNs’ knowledge about palliative care. Methods A descriptive cross-sectional study was carried out. Using social networks we distributed an online questionnaire with the Spanish version of Palliative Care Quiz for Nurses (PCQN-SV) throughout August 2015. Results A direct relationship between the number of responses and the questionnaire’s apparitions in each social network was found. Comparing the results obtai…
An automatic filtering algorithm for SURF-based registration of remote sensing images
2017
International audience; The registration of remote sensing images has been often a necessary step for further analyses of images taken at different times, different viewing geometry or with different sensors. For this task there exists many approaches. This paper focuses on the feature-based category of image registration methods. Particularly, we propose an improvement of the SURF algorithm on the point matching step. Indeed, in order to achieve a correct registration, a good matching of feature point is required. However The presence of outliers lead to a fail in the registration. Therefore, in this paper, we introduce an efficient method devoted to the detection and removal of such outli…
The categorization of amateur cyclists as research participants: findings from an observational study.
2018
Sampling bias is an issue for research involving cyclists. The heterogeneity of cyclist populations, on the basis of skill level and riding purpose, can generate incorrect inferences about one specific segment of the population of interest. In addition, a more accurate categorization would be helpful when physiological parameters are not available. This study proposes using self-reported data to categorize amateur cyclist types by varying skill levels and riding purposes, therefore improving sample selection in experimental studies. A total of 986 cyclists completed an online questionnaire between February and October 2016. Two-step cluster analyses were performed to generate distinct group…