Possibility for albedo estimation of exomoons: Why should we care about M dwarfs?

Occultation light curves of exomoons may give information on their albedo and hence indicate the presence of ice cover on the surface. Icy moons might have subsurface oceans thus these may potentially be habitable. The objective of our paper is to determine whether next generation telescopes will be capable of albedo estimations for icy exomoons using their occultation light curves. The success of the measurements depends on the depth of the moon's occultation in the light curve and on the sensitivity of the used instruments. We applied simple calculations for different stellar masses in the V and J photometric bands, and compared the flux drop caused by the moon's occultation and the estimated photon noise of next generation missions with 5 $\sigma$ confidence. We found that albedo estimation by this method is not feasible for moons of solar-like stars, but small M dwarfs are better candidates for such measurements. Our calculations in the J photometric band show that E-ELT MICADO's photon noise is just about 4 ppm greater than the flux difference caused by a 2 Earth-radii icy satellite in a circular orbit at the snowline of an 0.1 stellar mass star. However, considering only photon noise underestimates the real expected noise, because other noise sources, such as CCD read-out and dark signal become significant in the near infrared measurements. Hence we conclude that occultation measurements with next generation missions are far too challenging, even in the case of large, icy moons at the snowline of small M dwarfs. We also discuss the role of the parameters that were neglected in the calculations, e.g. inclination, eccentricity, orbiting direction of the moon. We predict that the first albedo estimations of exomoons will probably be made for large icy moons around the snowline of M4 -- M9 type main sequence stars.Comment: 13 pages, 6 figures, accepted for publication in A&

Determining Projections of Grain Boundaries from Diffraction Data in Transmission Electron Microscope

AbstractGrain boundaries (GB) are characterized by disorientation of the neighboring grains and the direction of the boundary plane between them. A new approach presented here determines the projection of GB that can be used to determine the latter one. The novelty is that an additional parameter of GB is quantified in addition to the ones provided by the orientation maps, namely the width of the projection of the GB is measured from the same set of diffraction patterns that were recorded for the orientation map, without the need to take any additional images. The diffraction patterns are collected in nanobeam diffraction mode in a transmission electron microscope, pixel-by-pixel, from an area containing two neighboring grains and the boundary between them. In our case, the diffraction patterns were recorded using the beam scanning function of a commercially available system (ASTAR). Our method is based on non-negative matrix factorization applied to the mentioned set of diffraction patterns. The method is encoded in a MATLAB environment, making the results easy to interpret and visualize. The measured GB-projection width is used to determine the orientation of the GB-plane, as given in the study by Kiss et al.</jats:p

Porosity and compatibility of repair mortars and Hungarian porous limestones

Abstract Porosity and water absorption of different binder/aggregate ratios of repair mortar and porous limestone were studied that were used in many Hungarian monuments. Different types of mortars were analyzed by using mercury intrusion porosimetry (MIP) and the water saturation method (WSM). Test results showed that there was a strong correlation between the absorption mechanism and the porosimetric characteristics. Mechanical properties of the tested mortars were observed earlier. Pore size distribution confirms that the total porosity increases with increasing aggregate content. Natural stones mainly have medium and large pore radii (1–100 μm) while repair mortars, even with increased aggregate ratio, have smaller pore radii (0.01–0.1 μm). The comparison of different data allows us to state that pore characteristics such as pore volume, pore geometry, pore size distribution and network connectivity are the key control factors of stone and mortar deterioration

Gazdanövénykört és betegségtüneteket meghatározó vírusgének analízise, különös tekintettel a cucumovírusokra = Analysis of the genetic determinants of cucumoviral host range and symptomatology

Növényi vírosok esetében a gazdanövénykört és a kialakuló vírustüneteket számos vírusgén befolyásolja. Gazdaságilag az egyik legjelentősebb vírusnemzetség esetén, a cucumovírusoknál különböző vírusgének patológiai jelentőségét vizsgáltuk. A szisztemikus terjedésben szerept játszó köpenyfehérje vizsgálata során az uborka mozaik vírus (cucumber mosac virus, CMV) köpenyfehérjéjének a virion felszínén lokalizálódó öt hurok régióját paradicsom magtalanság vírus (tomato aspermy virus, TAV) megfelelő régióira cserélve, majd pontmutánsokat készítve azonosítottuk, hogy a cucumovírusok szisztemikus mozgásában a 'B-'C hurok három aminosavának van kulcsszerepe. A CMV-Ns izolátuma hiperszenzitív reakciót (HR) indukál Nicotiana tabacum cv. Xanthi-nc és Nicotiana glutinosa növényeken. A HR kiváltásának genetikai determinánsaként az 1a fehérje 461 aminosavát azonosítottuk, majd az elicitor funkciót molekuláris modellezéssel tervezett mutáns vírusok felhasználásával vizsgáltuk. A jósolt részleges fehérjeszerkezet felhasználásával elemeztük a fertőzési kísérletek eredményeit. A földimogyoró satnyulás vírus (peanut stunt virus, PSV) akác izolátumának (PSV-Rp) teljes nukleinsav sorrendjét meghatároztuk. A PSV izolátumok homológia viszonyai és a rekombinációs vizsgálatok indokolták egy új, IV. PSV alcsoport kialakítása. | In the case of plant viruses symptoms and host range differences are affected by several different viral factors. We have analysed such viral determinants in the case of cucumoviruses inducing considerable harm to agriculture worldwide. To characterise the long-distance movement determinant of cucumoviral coat proteins (cp), 5 mutants were engineered into the Cucumber mosaic virus (CMV) cp bearing the corresponding Tomato aspermy virus (TAV) loops exposed on the surface of the virion. Three amino acids of the 'B-'C loop of the CP were identified as critical determinants for long-distance movement of cucumoviruses. The Ns-strain of CMV induces a hypersensitive response (HR) on Nicotiana tabacum cv. Xanthi-nc and on Nicotiana glutinosa. The genetic determinant of the HR induction was localised to amino acid 461 of the 1a protein and the elicitor function was characterized with a series of mutants based on molecular modeling. We analysed the results in terms of a predicted partial protein structure. The complete nucleotide sequence of Peanut stunt virus Robinia strain (PSV-Rp) was determined and compared to other PSV strains. Recombination breakpoint analysis revealed two recombination points on the RNA3. Based on our results we proposed to establish a forth PSV subgroup, and our work revealed that homologous recombination occurred in PSV evolution