Search results for "Star"
showing 10 items of 4285 documents
A preliminary study of agility in business and production - Cases of early-stage hardware startups
2018
[Context] Advancement in technologies, popularity of small-batch manufacturing and the recent trend of investing in hardware startups are among the factors leading to the rise of hardware startups nowadays. It is essential for hardware startups, companies that involve both software and hardware development, to be not only agile to develop their business but also efficient to develop the right products. [Objective] We investigate how hardware startups achieve agility when developing their products in early stages. [Methods] A qualitative research is conducted with data from 20 hardware startups. [Result] Preliminary results show that agile development is known to hardware entrepreneurs, howe…
iLocater: a diffraction-limited Doppler spectrometer for the Large Binocular Telescope
2016
We are developing a stable and precise spectrograph for the Large Binocular Telescope (LBT) named "iLocater." The instrument comprises three principal components: a cross-dispersed echelle spectrograph that operates in the YJ-bands (0.97-1.30 microns), a fiber-injection acquisition camera system, and a wavelength calibration unit. iLocater will deliver high spectral resolution (R~150,000-240,000) measurements that permit novel studies of stellar and substellar objects in the solar neighborhood including extrasolar planets. Unlike previous planet-finding instruments, which are seeing-limited, iLocater operates at the diffraction limit and uses single mode fibers to eliminate the effects of m…
Correcting the effect of stellar spots on ARIEL transmission spectra
2020
The goal of this study is to assess the impact of the stellar spots on the extraction of the planetary transmission spectra observed by ARIEL. We develop a method to model the stellar spectrum of a star in the presence of spots by using the out-of-transit observations. It is based on a chi squared minimization procedure of the out-of-transit spectrum on a grid of stellar spectra with different sizes and temperatures of the spots. The approach allows us also to study the temporal evolution of the spots when comparing stellar spectra observed at different epochs. We also present a method to correct the transit depth variations due to non-occulted stellar spots and estimate the error we introd…
Variable X-ray emission from the accretion shock in the classical T Tauri star V2129 Ophiuchi
2011
The soft X-ray emission from high density plasma in CTTS is associated with the accretion process. It is still unclear whether this high density cool plasma is heated in the accretion shock, or if it is coronal plasma fed/modified by the accretion process. We conducted a coordinated quasi-simultaneous optical and X-ray observing campaign of the CTTS V2129 Oph (Chandra/HETGS data to constrain the X-ray emitting plasma components, and optical observations to constrain the characteristics of accretion and magnetic field). We analyze a 200 ks Chandra/HETGS observation of V2129 Oph, subdivided into two 100 ks segments, corresponding to two different phases within one stellar rotation. The X-ray …
Cietvielu luminoforu molekulārais dizains
2022
Cietvielu luminoforu molekulārais dizains. Mazarevičs A., zinātniskie vadītāji Mg. chem. Leduskrasts K., Prof., Dr. chem. Sūna E. Maģistra darbs, 72 lapaspuses, 44 attēli, 11 tabulas, 38 literatūrās avoti, 1 pielikums. Latviešu valodā. Literatūras apskatā analizēti organiskie luminofori, luminiscence un fosforescence. Iekļauti organiskās fosforescences iegūšanas metožu piemēri izmantojot starpmolekulāru mijiedarbību veidošanu, smagā atoma efektu, kā arī heteroatomu ievadīšanu molekulā. Rezultātu izvērtējumā aprakstīta sintezēto savienojumu iegūšana un analizētas to luminiscentās īpašības. Eksperimentālajā daļā sintezēti 26 savienojumi, no kuriem luminiscentās īpašības noteiktas 13. No lumin…
What are the risk and protective factors for the well-being of adolescents with CF?
2021
La fibrosis quística (FQ) es una enfermedad crónica y hereditaria que compromete la vida de quienes la padecen, y se hace especialmente importante su impacto en la adolescencia. El afrontamiento que estos pacientes y sus familiares hagan de estas circunstancias que les han tocado vivir, puede mejorar o empeorar el curso y desenlace de la enfermedad. El objetivo es conocer los factores de riesgo y protectores que influyen en el bienestar de los adolescentes con FQ. Para ello se realizó una búsqueda bibliográfica de la literatura científica siguiendo la guía PRISMA en las siguientes bases de datos: Web of Science, ProQuest y Scopus. Se incluyeron artículos centrados en factores psicológicos d…
Analysis of the relationship between start of the rainy season and farmer's sowing strategy in the Niamey area and its impacts on the pearl millet yi…
2009
International audience; Relationship between start of the rainy season and farmer's planting date have been analysed at local scale through in situ daily rainfall records and agronomical measurement provided by on-farm survey at plot scale for 10 villages network located on the mesoscale AMMA-CATCH Niger site during the 2004-2007 rainy seasons. Many classical empirical methods of monsoon onset dectection (e.g. Benoit, Kowal, Sivakumar, Ati, Marteau, Balme, Sultan) and numerical methods based on crop model SARRAH have been compared to the observed farmer's sowing date. Results show that SARRAH and Balme mean onset date are close to sowing date. But spatial and temporal variability of the sow…
Phenotypic analysis of adults and eggs of Fasciola hepatica by computer image analysis system
2005
AbstractKnowledge of the morphological phenotypes of the liver fluke Fasciola hepatica (Trematoda: Digenea) is analysed. The influence of parasite age on its dimensions, the adult fluke growth model, variation in a biometric variable versus time, and variation in a biometric variable versus another biometric variable (allometric model) are revised. The most useful allometric model appears to be (y2m]#x2212;y2)/y2=c [(y1m−y1)/y1]b, where y1=body area or body length, y2=one of the measurements analysed, y1m, y2m=maximum values towards which y1 and y2, respectively, tend, and c, b=constants. A method based on material standardization, the measurement proposal and allometric analysis is detaile…
Anaemia in advanced chronic fasciolosis
2008
Abstract The association between fasciolosis-induced anaemia and related factors has been quantified in a rodent model. Haematological parameters were analysed in Wistar rats at 20 and 60 weeks post-infection (p.i.). Pigment stones and bile specimens were collected. Serum IgG1, IgG2a and IgE were determined in rat serum samples. Cytokine levels have been correlated with haematological parameters. The screening for gastrointestinal bleeding was carried out. Bacteriological bile cultures revealed viable bacteria in 53.8% of specimens at 60 weeks p.i. The results show that the type of anaemia in fasciolosis might be considered a biomarker of the chronicity period of the disease, changing from …
High risk of bacterobilia in advanced experimental chronic fasciolosis
2006
Fasciolosis is recognized as an important human disease. Wistar rats experimentally infected with Fasciola hepatica were examined using data obtained in the advanced chronic state of the disease (200, 300 and 400 days post-infection, dpi). Pigment stones (PS) and bile specimens were collected. The same procedure was applied in control rats. Liver tests were determined using stored serum samples. Bacteriological bile culture revealed viable bacteria (Escherichia coli, 45% of cases, Enterococcus faecalis, 45% and Klebsiella pneumoniae, 10%). The presence of bacterobilia was associated with liver serum enzymes, including aspartate aminotransferase (AST or SGOT), alanine aminotransferase (ALT o…