Search

Your search keyword '"Lasota J"' showing total 767 results
Start Over Author "Lasota J"
767 results on '"Lasota J"'

151. Forest habitats and forest types on chernozems in south-eastern Poland

Author

Lasota Jarosław, Błońska Ewa, Łyszczarz Stanisław, and Sadowy Adrian

Subjects
forest soil, habitat conditions, soil properties, trophic soil index, Agriculture
Abstract

The objective of the study is the presentation of the chemical properties of forest chernozems and the features of forest habitats developed on chernozems in south-eastern Poland. The assessment of the trophic status of chernozems was presented based on the Trophic Soil Index (SIG). Moreover, the paper presents the diversity of forest vegetation on chernozems. The research covered 15 plots from the habitat inventory performed for the Mircze and Strzelce Forest Districts (SE Poland). Habitat conditions were characterised on the research plots, with particular consideration of the soil and vegetation. The analysed soils were featured by the presence of thick humus horizons and the occurrence of calcium carbonate. High SIG values confirm the eutrophic status of the analysed soils. In general, fresh and wet habitats of broadleaved forests (Lśw and Lw), as well as fresh habitats of broadleaved upland forest (Lwyżśw) develop on chernozems in Poland. They are associated with multi-species broadleaved tree stands. The conducted research indicates that, in current environmental conditions, the potential plant community is oak-hornbeam forest with predominance of oak, hornbeam, and abundant admixtures of other broadleaved species. High trophic status of the analysed chernozems is confirmed by high bonitation of tree stands and richness of forest floor vegetation.

Published
2019
Full Text
View/download PDF

152. The centrifugal force reversal and X-ray bursts

Author

Abramowicz, M. A., Kluzniak, W., Lasota, J. -P., Abramowicz, M. A., Kluzniak, W., and Lasota, J. -P.

Abstract

Heyl (2000) made an interesting suggestion that the observed shifts in QPO frequency in type I X-ray bursts could be influenced by the same geometrical effect of strong gravity as the one that causes centrifugal force reversal discovered by Abramowicz and Lasota (1974). However, his main result contains a sign error. Here we derive the correct formula and conclude that constraints on the M(R) relation for neutron stars deduced from the rotational-modulation model of QPO frequency shifts are of no practical interest because the correct formula implies a weak condition R* > 1.3 Rs, where Rs is the Schwarzschild radius. We also argue against the relevance of the rotational-modulation model to the observed frequency modulations., Comment: 3 pages, Minor revisions, A&A Letters, in press

Published
2001
Full Text
View/download PDF

153. The disc instability model for X-ray transients: evidence for truncation and irradiation

Author

Dubus, G., Hameury, J. -M., Lasota, J. -P., Dubus, G., Hameury, J. -M., and Lasota, J. -P.

Abstract

We study the prospect of explaining the outbursts of Soft X-ray Transients (SXTs) by the thermal-viscous instability in a thin disc. This instability is linked to hydrogen ionization and is significantly changed when irradiation of the disc by X-rays from the inner regions is included. We present the first numerically reliable, physically consistent calculations of the outburst cycles which include the effects of accretion disc irradiation. The decay from outburst is governed by irradiation, as pointed out by King & Ritter (1998), leading to slow exponential decays. At the end of the outburst, the disc is severely depleted, which lengthens the time needed to rebuild mass to the critical density for an outburst. Despite this, the long recurrence times and quiescent X-ray luminosities of SXTs still require the inner disc to be replaced by another type of flow in quiescence, presumably a hot advection dominated accretion flow (ADAF). We include the effects of such truncation and show that the resulting lightcurves are conclusively similar to those of SXTs like A0620-00. We conclude that the two-alpha disc instability model provides an adequate description of the outbursts of SXTs when both truncation and irradiation are included. The values for the viscosities in outburst and in quiescence are comparable to those used in CVs. We discuss the model in the context of present observations., Comment: accepted for publication in A&A, 22 pages, 20 figures

Published
2001
Full Text
View/download PDF

183. Forest sites and forest types on rendzinas in Poland

Author

Lasota Jarosław, Błońska Ewa, and Pacanowski Piotr

Subjects
forest soils, lowland, upland and mountain sites, plant associations, Agriculture
Abstract

The article discusses the relationship between rendzinas and types of forest sites and plant communities in lowland, upland and mountain areas in Poland. Rendzinas as soils of forest sites play an important role in the uplands of southern Poland. In mountain areas, their preponderance is limited to the area of the Pieniny and the Western Tatras. The site-forming role of rendzinas in the upland areas depends mainly on geomorphological conditions. Typical rendzinas generally form eutrophic sites of multi-species oak-hornbeam forests, fertile beech forests and thermophilous beech forests. Rendzinas with lithological discontinuities usually create poorer form sites of mixed deciduous forests, which correspond to floristically poorer phytocenoses of acidophilous deciduous forests. In mountain areas, the climate and geomorphological processes form the zonation of vegetation and rendzinas. In vertical layout sites, the rendzinas change from fertile sites of fir and beech forests, through mesotrophic mixed forests sites, to spruce forest on limestone in the upper montane zone.

Published
2018
Full Text
View/download PDF

184. Steps toward determination of the size and structure of the broad-line region in active galactic nuclei. I. An 8 month campaign of monitoring NGC 5548 with IUE

Author

Clavel, J., Reichert, G. A., Alloin, D., Crenshaw, D. M., Kriss, G., Krolik, J. H., Malkan, M. A., Netzer, H., Peterson, B. M., Wamsteker, W., Altamore, A., Baribaud, T., Barr, P., Beck, S., Binette, L., Bromage, G. E., Brosch, N., Diaz, A. I., Filippenko, A. V., Fricke, K., Gaskell, C. M., Giommi, P., Glass, I. S., Gondhalekar, P., Hackney, R. L., Halpern, J. P., Hutter, D. J., Jorsater, S., Kinney, A. L., Kollatschny, W., Koratkar, A., Korista, K. T., Laor, A., Lasota, J. P., Leibowitz, E., Maoz, D., Martin, P. G., Mazeh, T., Meurs, E. J. A., Nair, A. D., O'Brien, P., Pelat, D., Perez, E., Perola, G. C., Ptak, R. L., Rodriguez-Pascual, P., Rosenblatt, E. I., Sadun, A. C., Santos-Lleo, M., Shaw, R. A., Smith, P. S., Stirpe, G. M., Stoner, R., Sun, W. H., Ulrich, M. -H, van Groningen, E., Zheng, W., Clavel, J., Reichert, G. A., Alloin, D., Crenshaw, D. M., Kriss, G., Krolik, J. H., Malkan, M. A., Netzer, H., Peterson, B. M., Wamsteker, W., Altamore, A., Baribaud, T., Barr, P., Beck, S., Binette, L., Bromage, G. E., Brosch, N., Diaz, A. I., Filippenko, A. V., Fricke, K., Gaskell, C. M., Giommi, P., Glass, I. S., Gondhalekar, P., Hackney, R. L., Halpern, J. P., Hutter, D. J., Jorsater, S., Kinney, A. L., Kollatschny, W., Koratkar, A., Korista, K. T., Laor, A., Lasota, J. P., Leibowitz, E., Maoz, D., Martin, P. G., Mazeh, T., Meurs, E. J. A., Nair, A. D., O'Brien, P., Pelat, D., Perez, E., Perola, G. C., Ptak, R. L., Rodriguez-Pascual, P., Rosenblatt, E. I., Sadun, A. C., Santos-Lleo, M., Shaw, R. A., Smith, P. S., Stirpe, G. M., Stoner, R., Sun, W. H., Ulrich, M. -H, van Groningen, E., and Zheng, W.

Abstract

The authors present emission-line and ultraviolet continuum observations of a type I Seyfert galaxy in which the time resolution is adequate for describing the character of variability. Using the IUE satellite, the nucleus of NGC 5548 was observed every 4 days for a period of 8 months. Its mean properties-continuum shape, line ratios-are not unusual for type I Seyfert galaxies, but it was found to be strongly variable. The ultraviolet continuum flux and broad emission line fluxes varied significantly, going through three large maxima and three deep minima. The great majority of all variations were well resolved in time. The data lend qualitative support to the view that photoionization by the nuclear continuum is responsible for driving the emission lines

Published
1991
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results