scholarly journals Asteroseismic potential of CHEOPS

2018 ◽  
Vol 620 ◽  
pp. A203 ◽  
Author(s):  
A. Moya ◽  
S. Barceló Forteza ◽  
A. Bonfanti ◽  
S. J. A. J. Salmon ◽  
V. Van Grootel ◽  
...  
Keyword(s):  
Time Series ◽  
Main Sequence ◽  
Uncertainty Reduction ◽  
Light Curves ◽  
Accuracy And Precision ◽  
Mass Uncertainty ◽  
The Impact ◽  
Host Stars

Context. Asteroseismology has been impressively boosted during the last decade mainly thanks to space missions such as Kepler/K2 and CoRoT. This has a large impact, in particular, in exoplanetary sciences since the accurate characterization of the exoplanets is convoluted in most cases with the characterization of their hosting star. In the decade before the expected launch of the ESA mission PLATO 2.0, only two important missions will provide short-cadence high-precision photometric time-series: NASA–TESS and ESA–CHEOPS missions, both having high capabilities for exoplanetary sciences. Aims. In this work we want to explore the asteroseismic potential of CHEOPS time-series. Methods. Following the works estimating the asteroseismic potential of Kepler and TESS, we have analysed the probability of detecting solar-like pulsations using CHEOPS light-curves. Since CHEOPS will collect runs with observational times from hours up to a few days, we have analysed the accuracy and precision we can obtain for the estimation of νmax. This is the only asteroseismic observable we can recover using CHEOPS observations. Finally, we have analysed the impact of knowing νmax in the characterization of exoplanet host stars. Results. Using CHEOPS light-curves with the expected observational times we can determine νmax for massive G and F-type stars from late main sequence (MS) on, and for F, G, and K-type stars from post-main sequence on with an uncertainty lower than a 5%. For magnitudes V <  12 and observational times from eight hours up to two days, the HR zone of potential detectability changes. The determination of νmax leads to an internal age uncertainty reduction in the characterization of exoplanet host stars from 52% to 38%; mass uncertainty reduction from 2.1% to 1.8%; radius uncertainty reduction from 1.8% to 1.6%; density uncertainty reduction from 5.6% to 4.7%, in our best scenarios.

scholarly journals The Diagnosis and Clinical Significance of Paragangliomas in Unusual Locations

2018 ◽  
Vol 7 (9) ◽  
pp. 280 ◽  
Author(s):  
Sylvia Asa ◽  
Shereen Ezzat ◽  
Ozgur Mete
Keyword(s):  
Malignant Disease ◽  
Correct Diagnosis ◽  
Neuroendocrine Neoplasms ◽  
Clinical Implications ◽  
Bladder Tumors ◽  
Primary Tumors ◽  
Anatomic Locations ◽  
The Impact

Paragangliomas are neuroendocrine neoplasms, derived from paraganglia of the sympathetic and parasympathetic nervous systems. They are most commonly identified in the head and neck, being most frequent in the carotid body, followed by jugulotympanic paraganglia, vagal nerve and ganglion nodosum, as well as laryngeal paraganglia. Abdominal sites include the well-known urinary bladder tumors that originate in the Organ of Zuckerkandl. However, other unusual sites of origin include peri-adrenal, para-aortic, inter-aortocaval, and paracaval retroperitoneal sites, as well as tumors in organs where they may not be expected in the differential diagnosis of neuroendocrine neoplasms, such as thyroid, parathyroid, pituitary, gut, pancreas, liver, mesentery, lung, heart and mediastinum. The distinction of these lesions from epithelial neuroendocrine neoplasms is critical for several reasons. Firstly, the determination of clinical and biochemical features is different from that used for epithelial neuroendocrine tumors. Secondly, the genetic implications are different, since paragangliomas/pheochromocytomas have the highest rate of germline susceptibility at almost 40%. Finally, the characterization of metastatic disease is unique in these highly syndromic lesions. In this review, we summarize updated concepts by outlining the spectrum of anatomic locations of paragangliomas, the importance of morphology in establishing the correct diagnosis, the clinical implications for management, and the impact of genetics on the distinction between multifocal primary tumors compared with malignant disease.

scholarly journals CHARACTERIZATION OF LAND COVER SEASONALITY IN SENTINEL-1 TIME SERIES DATA

2020 ◽  
Vol V-3-2020 ◽  
pp. 97-104
Author(s):  
C. Dubois ◽  
M. M. Mueller ◽  
C. Pathe ◽  
T. Jagdhuber ◽  
F. Cremer ◽  
...  
Keyword(s):  
Time Series ◽  
Land Cover ◽  
Time Series Data ◽  
Coniferous Forest ◽  
Series Data ◽  
Urban Land Cover ◽  
Multi Temporal ◽  
Forested Areas

Abstract. In this study, we analyze Sentinel-1 time series data to characterize the observed seasonality of different land cover classes in eastern Thuringia, Germany and to identify multi-temporal metrics for their classification. We assess the influence of different polarizations and different pass directions on the multi-temporal backscatter profile. The novelty of this approach is the determination of phenological parameters, based on a tool that has been originally developed for optical imagery. Furthermore, several additional multitemporal metrics are determined for the different classes, in order to investigate their separability for potential multi-temporal classification schemes. The results of the study show a seasonality for vegetation classes, which differs depending on the considered class: whereas pastures and broad-leaved forests show a decrease of the backscatter in VH polarization during summer, an increase of the backscatter in VH polarization is observed for coniferous forest. The observed seasonality is discussed together with meteorological information (precipitation and air temperature). Furthermore, a dependence of the backscatter of the pass direction (ascending/descending) is observed particularly for the urban land cover classes. Multi-temporal metrics indicate a good separability of principal land cover classes such as urban, agricultural and forested areas, but further investigation and use of seasonal parameters is needed for a distinct separation of specific forest sub-classes such as coniferous and deciduous.

scholarly journals Characteristic diffuse scattering from distinct line roughnesses

2017 ◽  
Vol 50 (6) ◽  
pp. 1766-1772 ◽  
Author(s):  
Analía Fernández Herrero ◽  
Mika Pflüger ◽  
Jürgen Probst ◽  
Frank Scholze ◽  
Victor Soltwisch
Keyword(s):  
Extreme Ultraviolet ◽  
Structural Elements ◽  
Line Edge Roughness ◽  
Optical Elements ◽  
Angle Scattering ◽  
Edge Roughness ◽  
Angular Scattering ◽  
The Impact

Lamellar gratings are widely used diffractive optical elements; gratings etched into Si can be used as structural elements or prototypes of structural elements in integrated electronic circuits. For the control of the lithographic manufacturing process, a rapid in-line characterization of nanostructures is indispensable. Numerous studies on the determination of regular geometry parameters of lamellar gratings from optical and extreme ultraviolet (EUV) scattering highlight the impact of roughness on the optical performance as well as on the reconstruction of these structures. Thus, a set of nine lamellar Si gratings with a well defined line edge roughness or line width roughness were designed. The investigation of these structures using EUV small-angle scattering reveals a strong correlation between the type of line roughness and the angular scattering distribution. These distinct scattering patterns open new paths for the unequivocal characterization of such structures by EUV scatterometry.

scholarly journals Activity of (2060) Chiron possibly caused by impacts?

2018 ◽  
Vol 475 (2) ◽  
pp. 2512-2518 ◽  
Author(s):  
Stefan Cikota ◽  
Estela Fernández-Valenzuela ◽  
Jose Luis Ortiz ◽  
Nicolás Morales ◽  
René Duffard ◽  
...  
Keyword(s):  
Time Series ◽  
Mass Loss ◽  
Surface Brightness ◽  
Light Curves ◽  
Loss Mechanism ◽  
Long Tail ◽  
Absolute Magnitudes ◽  
The Impact ◽  
Possible Cause ◽  
Calar Alto

Abstract The centaur 95P/(2060) Chiron is showing comet-like activity since its discovery, but the mass-loss mechanisms triggering its activity remained unexplained. Although the collision rates in the centaur region are expected to be very low, and impacts are thought not to be responsible for the mass-loss, since the recent indications that Chiron might possess a ring similar to Chariklo's, and assuming that there is debris orbiting around, the impact triggered mass-loss mechanism should not be excluded as a possible cause of its activity. From time series observations collected on Calar Alto Observatory in Spain between 2014 and 2016, we found that the photometric scatter in Chiron's data is larger than a control star's scatter, indicating a possible microactivity, possibly caused by debris falling back to Chiron's surface and lifting small clouds of material. We also present rotational light curves, and measurements of Chiron's absolute magnitudes, which are consistent with the models supporting the presumption that Chiron possesses rings. By co-adding the images acquired in 2015, we have detected an ∼5 arcsec long tail, showing a surface brightness of 25.3 mag(V) arcsec−2.

Flexible Variable Star Extractor - new software for variable stars detection using CCD photometry

2017 ◽  
Vol 7 (1-2) ◽  
pp. 3-5
Author(s):  
V. Breus
Keyword(s):  
Time Series ◽  
Computer Program ◽  
Variable Star ◽  
Variable Stars ◽  
Light Curves ◽  
Multiple Comparison ◽  
Ccd Photometry ◽  
Comparison Stars ◽  
The Impact ◽  
Outlying Point

We developed a computer program for variable stars detection using CCD photometry. It works with "varfind data" that could be exported after processing CCD frames using C-Munipack. The program chooses the comparison stars automatically, processes all time series using multiple comparison stars to get final light curves. We developed few filters and criteria that allow reducing the impact of outlying points, imaging artefacts and low quality CCD frames without careful manual time series reduction. We implemented the calculation of various variable detection indices. The pipeline has a possibility of plotting a two-channel diagram of selected pair of indices or mean brightness of the star for manual check if any outlying point is a variable candidate. The program is available at http://uavso.org.ua/varsearch/.

Assessment of Measuring Errors in Strain Fields Obtained via DIC on Planar Sheet Metal Specimens with a Non-Perpendicular Camera Alignment

2011 ◽  
Vol 70 ◽  
pp. 165-170 ◽  
Author(s):  
Pascal Lava ◽  
Sam Coppieters ◽  
Yue Qi Wang ◽  
Paul van Houtte ◽  
Dimitri Debruyne
Keyword(s):  
Sheet Metal ◽  
Biaxial Loading ◽  
Image Plane ◽  
Displacement Fields ◽  
Strain Fields ◽  
Accuracy And Precision ◽  
Camera View ◽  
Plane Displacement ◽  
The Impact

The determination of strain fields based on displacement components obtained via 2D-DIC is subject to several errors that originate from various sources. In this contribution, we study the impact of a non-perpendicular camera alignment to a planar sheet metal specimen’s surface subject to biaxial loading conditions. The errors are estimated in a numerical experiment. To this purpose, deformed images - that were obtained by imposing finite element (FE) displacement fields on an undeformed image - are numerically rotated for various Euler angles. It is shown that a 3D-DIC stereo configuration induces a substantial compensation for the introduced image-plane displacement gradients. However, higher strain accuracy and precision are obtained - up to the level of a perfect perpendicular alignment - in a proposed ”rectified” 2D-DIC setup. This compensating technique gains benefit from both 2D-DIC (single camera view, basic amount of correlation runs, no cross-camera matching nor triangulation) and 3D-DIC (oblique angle compensation).

scholarly journals Future Observations of Transits and Light Curves from Space

2008 ◽  
Vol 4 (S253) ◽  
pp. 319-328 ◽  
Author(s):  
Charles A. Beichman ◽  
Tom Greene ◽  
John Krist
Keyword(s):  
Thermal Structure ◽  
Light Curves ◽  
Atmospheric Composition ◽  
Light Curve Analysis ◽  
James Webb Space Telescope ◽  
Sky Survey ◽  
Future Space ◽  
Host Stars

AbstractA variety of new observational opportunities have made transit and more generally light curve analysis central to the study of exoplanets. Talks at this IAU 253 Symposium have dramatically highlighted the measurement of the radius, density, atmospheric composition and atmospheric thermal structure, presently for relatively large, hot planets, but soon for smaller planets orbiting further from their host stars. On-going and future space observations will play a key role in the detection and characterization of these planetary systems. After a brief review, I focus on two topics: the need for a sensitive all-sky survey for planets transiting the brightest, closest stars and the follow-up opportunities afforded by the James Webb Space Telescope (JWST).

scholarly journals Elemental concentration via portable x-ray fluorescence spectrometry: Assessing the impact of water content

2019 ◽  
Vol 43 ◽  
Author(s):  
Monna Lysa Teixeira Santana ◽  
Geila Santos Carvalho ◽  
Luiz Roberto Guimarães Guilherme ◽  
Nilton Curi ◽  
Bruno Teixeira Ribeiro
Keyword(s):  
Water Content ◽  
Atomic Number ◽  
Certified Reference Materials ◽  
Chemical Characterization ◽  
X Ray ◽  
Influence Of Water ◽  
Corrected Data ◽  
The Impact

ABSTRACT Portable X-ray fluorescence (pXRF) analysis can be considered one of the main recent advances for chemical characterization of earth materials. The water content of the samples can affect the pXRF performance. As a novelty, we aimed to establish relationships (linear regression) between the effect of water content on pXRF results and atomic number (Z) of the elements. Three certified reference materials (CRM) were investigated: OREAS 100a, OREAS 101a, and OREAS 101b. These materials were saturated (0.68 g g-1) with distilled water and left to air-dry naturally. During the drying, the elemental concentrations (C) were determined at different water contents using a pXRF spectrometer. For each water content, the ratio Cwet/Cdry was determined and plotted against the water content. The attenuation coefficient (σ) was also determined. High σ values mean more influence of water content upon measurement element concentration. The obtained recovery rates allowed a qualitative determination. The concentration for the most elements reduced linearly with increasing water content. A predictable behavior of the water content on pXRF results as function of atomic number was not found. Elements identified by Lα spectral line with highest Z were more impacted by water content than elements identified by Kα line with lowest Z. Ti, Cr and Fe was not significantly influenced by water content, and Sr was the most impacted. Our findings contribute to decision-making before characterization earth materials via pXRF, obliging the use of dry samples for determination of impacted elements or by using moisture-corrected data.

scholarly journals NMR Tracing of Food Geographical Origin: The Impact of Seasonality, Cultivar and Production Year on Data Analysis

Separations ◽  
2021 ◽  
Vol 8 (12) ◽  
pp. 230
Author(s):  
Olimpia Masetti ◽  
Angela Sorbo ◽  
Luigi Nisini
Keyword(s):  
Data Analysis ◽  
Nmr Spectroscopy ◽  
Geographical Origin ◽  
Soil Composition ◽  
Multivariate Statistical ◽  
Preliminary Study ◽  
The Impact

The traceability of typical foodstuffs is necessary to protect high quality of traditional products. It is well-known that several factors could influence metabolites content in certified foods, but soil composition, altitude, latitude and coded production protocols constitute the territorial conditions responsible for the peculiar organoleptic and nutritional properties of labelled foods. Instead, regardless of origin, seasonality, cultivar, collection year can affect all agricultural products, so it is appropriate to include them in data analysis in order to obtain a correct interpretation of the differences linked to growing areas alone. Therefore, it is useful to use a flexible all-round technique, and NMR spectroscopy coupled with multivariate statistical analysis is considered a powerful means of assessing food authenticity. The purpose of this review is to investigate the relevance of year, cultivar, and seasonal period in the determination of food geographical origin using NMR spectroscopy. The strategy for testing these three factors may differ from author to author, but a preliminary study of cultivar or collection year effects on NMR spectra is the most popular method before starting the geographical characterization of samples. In summary, based on the available literature, the most significant influence is due to cultivar, followed by harvesting year, however seasonality is not considered a source of variability in data analysis.

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