Assessment of high speed internet for remote sensing data acquisition and exchange in Colombia and Latin America

New remote sensing platforms and data programs have dramatically increased the availability of satellite image data for analysis of climate, agriculture, environment and society. Particularly important new sensor systems include the USA’s MODIS system, Brazil and China’s CBER platform, and India’s IRS satellite. These and other systems have created considerable benefits to the international community of remote sensing analysts. Today, we have more data with greater options regarding spatial, radiometric and temporal resolution. While having these greater options is a positive development, substantial problems remain in acquiring and managing large data volumes. Data providers and consumers must support significant costs in copying remote sensing data to tapes and disks. Internet transfer of satellite imagery is only possible on broadband networks. Even then, download times can be considerable. Downloads may be interrupted if the Internet connections are unstable. How can we improve the acquisition of large volumes of remote sensing data for environmental analysis? What alternatives are available to remote sensing researchers to acquire near-real time satellite imagery for research use? This paper assesses the potential of high-speed Internet as a medium for transferring large satellite imagery data sets between the United States and Colombia, between Colombia and other Latin American countries and within Colombia. Academic and research networks have led developments in high-speed Internet. Many countries throughout the world are installing the infrastructure needed to develop these networks. In the United States this system is referred to as Internet 2. Latin American countries are developing a system called RedCLARA (Cooperación Latinoamerican

The relationship between indoor and outdoor levels of PM10 and its chemical composition at schools in a coastal region in Spain

PM10 levels and its chemical composition were studied inside and outdoor of seven primary schools (3 in urban environment, 3 in industrial environment, 1 in rural environment) located in the Mediterranean coast in an area with an important industrial nucleus dedicated to the treatment of raw mineral materials. The main objective of this work is a comparison between these levels obtained inside and outside schools and also asses the influence of various natural and anthropogenic emission sources on particles concentrations found inside. The indoor airborne samples were collected using RespiCon TM. In the three outdoor sampling stations was used a minivol air sampler type 3.1 LVS of Derenda. PM10 Chemical composition was obtained by ICP-MS (elements) and ion chromatography The ratio I/O (indoor/outdoor) has been calculated taking into account only the samples taken in the same conditions. In all schools the ratio I/O for PM10 was greater than unity (between 1.3 and 7.8), indicating that existed significant indoor sources of these particles. In the three schools located in the industrial environment were collected PM10 samples inside and outside in non-teaching periods. Comparing the values of I/O when the classrooms were unoccupied with respect to the average value of these same schools when the classrooms are occupied, the behaviour is different depending on the location. On the other hand, a sample in an industrial school was obtained when some infrastructure works were being carried out outside of school. This caused a significant increase in the concentration of particles in the interior (I/O ¼ 19.9). From the levels of As, Ni, Cd, Pb, Al, B, Zn, Mg, Sb, F , ClO2-, NO3- and SO4 2- in PM10 inside and outside of each school, also the ratios I/O were calculated. These chemical ratios I/O were higher than unity in all cases and generally higher than those recorded in the case of PM10. Finally, Pearson correlation coefficients (r) between the elements and anions and the PM10, and between the different elements and anions were calculated for the purpose of establishing the existence of common emission sources

Evidence for enhanced chromospheric Ca II H & K emission in stars with close-in extrasolar planets

The planet-star interaction is manifested in many ways. It was found out that a close-in exoplanet causes small but measurable variability in the cores of a few lines in the spectra of several stars which corresponds to the orbital period of the exoplanet. Stars with and without exoplanets may have different properties. The main goal of our study is to search for influence which exoplanets might have on atmospheres of their host stars. Unlike the previous studies, we do not study changes in the spectrum of a host star or differences between stars with and without exoplanets. We aim to study a large number of stars with exoplanets, current level of their chromospheric activity and look for a possible correlation with the exoplanetary properties. To analyse the chromospheric activity of stars we exploit our own (2.2m ESO/MPG telescope) and publicly available archival spectra (Keck Observatory Archive), measure the equivalent widths of the cores of Ca II H and K lines and use them as a tracer of their activity. Subsequently, we search for their dependence on the orbital parameters and mass of the exoplanet. We found a statistically significant evidence that the equivalent width of the Ca II K line emission and log R'_{HK} activity parameter of the host star varies with the semi-major axis and mass of the exoplanet. Stars with T_eff <= 5500 K having exoplanets with semi-major axis a <= 0.15 AU (P_orb <= 20 days) have a broad range of Ca II K emissions and much stronger emission in general than stars at similar temperatures but with higher values of semi-major axes. Ca II K emission of cold stars (T_eff <= 5500 K) with close-in exoplanets (a <= 0.15 AU) is also more pronounced for more massive exoplanets. The overall level of the chromospheric activity of stars may be affected by their close-in exoplanets. Stars with massive close-in exoplanets may be more active.Comment: 9 pages, 8 figures, 1 tabl

The Mass-Radius Relationship for Very Low Mass Stars: Four New Discoveries from the HATSouth Survey

We report the discovery of four transiting F-M binary systems with companions between 0.1-0.2 Msun in mass by the HATSouth survey. These systems have been characterised via a global analysis of the HATSouth discovery data, combined with high-resolution radial velocities and accurate transit photometry observations. We determined the masses and radii of the component stars using a combination of two methods: isochrone fitting of spectroscopic primary star parameters, and equating spectroscopic primary star rotation velocity with spin-orbit synchronisation. These new very low mass companions are HATS550-016B (0.110 -0.006/+0.005 Msun, 0.147 -0.004/+0.003 Rsun), HATS551-019B (0.17 -0.01/+0.01 Msun, 0.18 -0.01/+0.01 Rsun), HATS551-021B (0.132 -0.005/+0.014 Msun, 0.154 -0.008/+0.006 Rsun), HATS553-001B (0.20 -0.02/+0.01 Msun, 0.22 -0.01/+0.01 Rsun). We examine our sample in the context of the radius anomaly for fully-convective low mass stars. Combining our sample with the 13 other well-studied very low mass stars, we find a tentative 5% systematic deviation between the measured radii and theoretical isochrone models.Comment: 17 pages, 8 figures, accepted for publication in MNRA

Observability of the General Relativistic Precession of Periastra in Exoplanets

The general relativistic precession rate of periastra in close-in exoplanets can be orders of magnitude larger than the magnitude of the same effect for Mercury. The realization that some of the close-in exoplanets have significant eccentricities raises the possibility that this precession might be detectable. We explore in this work the observability of the periastra precession using radial velocity and transit light curve observations. Our analysis is independent of the source of precession, which can also have significant contributions due to additional planets and tidal deformations. We find that precession of the periastra of the magnitude expected from general relativity can be detectable in timescales of <~ 10 years with current observational capabilities by measuring the change in the primary transit duration or in the time difference between primary and secondary transits. Radial velocity curves alone would be able to detect this precession for super-massive, close-in exoplanets orbiting inactive stars if they have ~100 datapoints at each of two epochs separated by ~20 years. We show that the contribution to the precession by tidal deformations may dominate the total precession in cases where the relativistic precession is detectable. Studies of transit durations with Kepler might need to take into account effects arising from the general relativistic and tidal induced precession of periastra for systems containing close-in, eccentric exoplanets. Such studies may be able to detect additional planets with masses comparable to that of Earth by detecting secular variations in the transit duration induced by the changing longitude of periastron.Comment: 13 pages, 5 figures. Accepted for publication in Ap