Search results for "satellite"

Multipactor Analysis in Coaxial Waveguides for Satellite Applications using Frequency-Domain Methods

2006

This work presents the analysis, manufacturing and testing of a coaxial sample in order to investigate the multipactor effect in this kind of waveguide structures. Several in-home and commercial software have been used to design a quarter-wave transformer coaxial circuit centered at 1.35 GHz. The multipactor analysis of this device has been carried out allowing the prediction of the RF breakdown multipactor threshold. Moreover, the multipactor onset of such a prototype has been measured showing a very good agreement with our simulations. In addition to this, comparison has been also done with results from the technical literature fully validating the new algorithm developed.

NMR Spectroscopic and quantum chemical characterization of the (E)- and (Z)- isomers of the penta-1,3-dienyl-2-cation

2003

Dilute solutions of the (E )− and (Z )− isomers of pent-1,3-dienyl-2-cations (1) were obtained from reaction of 4-chloro-1,2-pentadiene (2) with SbF5 in SO2ClF/SO2F2 at −135 °C using high-vacuum co-condensation techniques. The experimental NMR spectra of the mixture of the two isomers were compared with quantum chemical 13C NMR chemical shift calculations at HF-SCF, MP2, CCSD and CCSD(T) levels using MP2/tzp geometries. Quantum chemical shift calculations were performed with a tzp basis (9s5p1d/5s3p1d) for carbon and a dz basis (4s/2s) for hydrogen using gauge-including atomic orbitals (GIAOs). The HF-SCF calculations deviate significantly for the positively charged carbon atoms of the ally…

Low effective population sizes and limited connectivity inxerothermic beetles: implications for the conservation ofan endangered habita

2014

Fragmentation and isolation may have detrimental effects on the viability of populations. Xerothermic grasslands, which are extra-zonal analogues of steppes, are among Europe's most endangered natural environments. Information about connectivity between the remaining habitat patches is critical for effective conservation planning. However, very little is known about the actual levels of isolation of individual xerothermic patches at the inter-regional and local scale. In this study, 16 microsatellite loci were used to investigate genetic diversity, structuring, effective sizes (Ne), and connectivity among populations of the weevil Centricnemus leucogrammus at various geographic scales. Anal…

Land surface temperature derived from airborne hyperspectral scanner thermal infrared data

2006

Abstract The AHS (airborne hyperspectral scanner) instrument has 80 spectral bands covering the visible and near infrared (VNIR), short wave infrared (SWIR), mid-infrared (MIR), and thermal infrared (TIR) spectral range. The instrument is operated by Instituto Nacional de Tecnica Aerospacial (INTA) and it has been involved in several field campaigns since 2004. The main goal of this paper is to analyze the feasibility of retrieving land surface temperature from the 10 AHS thermal infrared bands, from 71 to 80, located in the region between 8 and 13 μm. For this purpose, three different methods have been considered: (i) the single-channel method, which uses only one thermal band; (ii) the sp…

Glial precursors clear sensory neuron corpses during development via Jedi-1, an engulfment receptor

2009

During the development of peripheral ganglia, 50% of the neurons that are generated undergo apoptosis. How the massive numbers of corpses are removed is unknown. We found that satellite glial cell precursors are the primary phagocytic cells for apoptotic corpse removal in developing mouse dorsal root ganglia (DRG). Confocal and electron microscopic analysis revealed that glial precursors, rather than macrophages, were responsible for clearing most of the dead DRG neurons. Moreover, we identified Jedi-1, an engulfment receptor, and MEGF10, a purported engulfment receptor, as homologs of the invertebrate engulfment receptors Draper and CED-1 expressed in the glial precursor cells. Expression …

From the Reference SEU Monitor to the Technology Demonstration Module On-Board PROBA-II

2008

The reference SEU Monitor system designed and presented in 2005 (R. H. SOslashrensen, F.-X. Guerre, and A. Roseng ldquoDesign, testing and calibration of a reference SEU monitor system,rdquo in Proc. RADECS, 2005, pp. B3-1-B3-7) has now been used by many researchers at many radiation test sites and has provided valuable calibration data in support of numerous projects. As some of these findings and results give new insight into improved inter-facility calibrations and provide additional inputs into ongoing SEE research, a few of the more interesting cases are presented. Furthermore the dasiadetector elementpsila, the Atmel AT60142F SRAM, now in a hybrid configuration, will form the key dete…

NMR Spectrum and Line Shape of Two Interacting Two-Spin Systems in Crystals

1967

Predicting and mapping human risk of exposure to

2019

Background Tick-borne diseases have become increasingly common in recent decades and present a health problem in many parts of Europe. Control and prevention of these diseases require a better understanding of vector distribution. Aim Our aim was to create a model able to predict the distribution of Ixodes ricinus nymphs in southern Scandinavia and to assess how this relates to risk of human exposure. Methods We measured the presence of I. ricinus tick nymphs at 159 stratified random lowland forest and meadow sites in Denmark, Norway and Sweden by dragging 400 m transects from August to September 2016, representing a total distance of 63.6 km. Using climate and remote sensing environmental …

The synergy of water quality and sea surface currents data in determining the spatio-temporal evolution of large-scale circulation features

2014

Chlorophyll-a (CHL-a) and Sea Surface Temperature (SST), amongst others, are proxies or indicators for water quality and can be easily retrieved synoptically and almost in near-real time through satellite remote-sensing. However, as they evolve in space and time in response to winds and currents, a full resolution of the temporal and spatial scales of these latters is required and their influence in shaping the distribution of water quality parameters needs to be assessed. While providing synoptic views and revealing mesoscale features, satellites suffer, indeed, from inadequate representation of sub-grid physical processes and lack of temporal resolution. Conventional point-wise measuremen…

Maximum and Actual Evapotranspiration for Barley (Hordeum vulgare L.) through NOAA Satellite Images in Castilla-La Mancha, Spain

1996

Abstract An easy-to-follow methodology is developed for the assessment of regional evapotranspiration in Castilla-La Mancha, a semi-arid region of Spain. The methodology is applied to barley crops to monitor the irrigation scheduling over the region, by using remote sensing techniques supplemented by ground measurements. The methodology can be based on either of two models. In the first one, established by Caselles and Delegido, 1 the reference evapotranspiration, ET o , derives from the expression ET o = AR g (T a ) m a x + BR g + C where A, B and C are empirical coefficients, depending on climatic parameters and determined for each region; R g is the daily global radiation; and ( T a ) m …