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1

Buckminster Fullerene and Interstellar Extinction

Gnaciński P.

Acta Astronomica

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2023

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Vol. 73, No. 2

179--186

EN

Most of over 500 Diffuse Interstellar Bands (DIBs) can not be assigned to any carrier. Only the infrared DIBs at 9348-9632 Å are known to be absorption lines of the buckminster fullerene cation C60+. We show that equivalent width of the 9577 Å DIB is correlated with the bump area on the ultraviolet extinction curve and with interstellar reddening E(B-V). Physical conditions must be similar for forming dust particles responsible for the UV-bump and forming C60+.

2

Environmental Crimes of Early Romanian Communism: Focus on the Enemies of Agriculture

Petrişor Alexandru-Ionuţ, Tîrzman Elena

Problemy Ekorozwoju

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2019

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Vol. 14, nr 1

175--184

EN

The early beginning of the communist regime in Romania was influenced by transformations of agriculture (including husbandry and fishing), forced to develop intensively (replacing traditional technologies with mechanical ones) and extensively (by taking over natural systems, such as the wetlands). Since the yield did not increase as expected, the conflict with nature was aggravated by finding enemies among the species situated at the top of food chains, blamed for the losses. In order to expedite the outcomes of fighting against these species, media campaigns were developed in parallel with awards given to hunters and people who became part of the war. This paper attempts to correlate the environmental impact of campaigns against certain species with the loss of biodiversity based on statistical data. The analysis indicated that there were direct campaigns to eliminate species conflicting with economy and collateral victims. Each case study illustrates a different point; bustards were eliminated by carelessness (although protected, their status was not enforced); the pelican was eliminated due to insufficient knowledge and contrasting recommendations; and wolf was sentenced to death consciously. The results indicate that although many authors parallel nowadays communist and environmentalist policies, the real communist practices had a strong deleterious environmental impact despite a pro-environmentalist appearance.

PL

Początkom reżimu komunistycznego w Rumunii towarzyszyły istotne transformacje w rolnictwie (odnoszące się m.in. do hodowli i rybołówstwa), będące zarazem intensywne (mechanizacja w miejsce tradycyjnych metod gospodarowania) i ekstensywne (przekształcanie naturalnych ekosystemów, takich jak mokradła). Ponieważ plony nie wzrosły zgodnie z oczekiwaniami, konflikt z naturą został wzmocniony przez poszukiwanie wrogów wśród gatunków znajdujących się na szczycie łańcucha pokarmowego i obwinianie ich winą za straty. W celu poprawy rezultatów walki z tymi gatunkami, przygotowano kampanie medialne, równolegle wprowadzając nagrody dla myśliwych i innych osób, które stały się częścią wojny. W tym artykule, opierając się na danych statystycznych, podjęto próbę połączenia przyrodniczych skutków wspomnianych kampanii z ich wpływem na zmniejszenie bioróżnorodności. Przeprowadzona analiza wykazała, ze wśród przeprowadzonych kampanii medialnych wskazać można na te, które miały na celu wyeliminowanie konkretnych gatunków, nie pasujących do przyjętej ekonomii. Każdy przypadek odzwierciedla inne uwarunkowania; dropie zostały wyeliminowane przez niedbalstwo (chronione tylko formalnie, a nie w rzeczywistości); Pelikan został wyeliminowany z powodu niewystarczającej wiedzy i sprzecznych zaleceń; a wilk został skazany na śmierć świadomie. Należy podkreślić, że choć wielu autorów promuje obecnie politykę komunistyczną i ekologiczną, to rzeczywiste praktyki komunistyczne wywarły zdecydowanie szkodliwy wpływ na środowisko, pomimo ich pozornie proekologicznego wyglądu.

3

On the Distance Measurements in the Thin Milky Way Disk

Krełowski J., Strobel A., Galazutdinov G. A., Musaev F., Bondar A.

Acta Astronomica

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2018

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Vol. 68, No. 3

285--300

EN

We present a test how far the direct, trigonometric parallax measurements and those, based on interstellar CaII H and K lines lead to distances to OB stars similar to those, based on spectrophotometrically determined ones. For this we use relatively nearby objects where the extinction effects are negligible. A test is based on observations of interstellar CaII H and K lines, that determine distances, in spectra of bright, nearby objects, free of extinction effects. For these objects one can find also trigonometric parallaxes. CaII H and K lines are weak in spectra of nearby stars and thus measurable only in high S/N ratio spectra. Such spectra being at our disposal also allow us to check the spectral classification of our targets and thus to comment the observed differences between distances acquired using different methods. Using four methods, we determined distances to nearly fifty B0-5 type stars, practically free of any extinction effects. We demonstrate that direct, astrometric, CaII H and K and spectrophotometric distances agree reasonably well in the absence of substantial interstellar extinction and when spectral classification is reliable. Apparently the absolute magnitude calibration, provided by Schmidt-Kaler, appears to be correct.

4

On the Distance Measurements toward Young Milky Way Objects. I. Study of IC 2944

Krełowski J., Strobel A., Godunova V., Bondar A.

Acta Astronomica

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2017

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Vol. 67, No. 4

379--396

EN

We compare distances to a very young stellar aggregate, IC 2944, using three methods: direct parallaxes of Gaia, spectrophotometric parallax and our method based on intensities of interstellar CaII lines. The discrepancies between spectrophotometric distances and those, based on CaII K and H lines, were already reported. The interstellar CaII H and K lines allow one to determine both distances and radial velocities of the intervening clouds. Thus, these data allow us to check the aggregate membership. It is also possible to check the spectral classification of considered targets which is necessary for spectrophotometric parallaxes. Using three methods, we determined distances to IC 2944 stars. We demonstrate that CaII based distances agree very well with the kinematic ones but are generally much smaller than the spectrophotometric ones. We conclude that the majority of IC 2944 objects is obscured by clouds producing neutral ("gray") extinction which diminishes their brightness exactly like extended distances. This influences spectrophotometric parallaxes while those, based on the CaII lines, do not depend on extinction and this method seems to be the most reliable one inside the thin disk of our Galaxy. The Gaia trigonometric parallaxes lead to distances similar to those obtained using the CaII method if their errors are reasonably small.

5

Genus-level versus species-level extinction rates

Trammer J.

Acta Geologica Polonica

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2016

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Vol. 66, no. 3

261--265

EN

The average extinction rates of index species per m. y. are computed by means of a count-of-biozones metric (Trammer 2014). These rates and the average extinction rates of genera belonging to biostratigraphically important groups, calculated according to three different methods, show congruent rises and falls from the Cambrian to the Neogene. The extinction rates of genera are, thus, a relatively good predictor of species extinction rates.

6

Gray Extinction in the Orion Trapezium

Krełowski J., Galazutdinov G. A., Strobel A., Mulas G.

Acta Astronomica

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2016

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Vol. 66, No. 4

469--480

EN

We estimated distances to several Orion Trapezium stars using our CaII-method and confirm the distance recommended by Menten et al. However, we found that in the case of HD 37020 both individual distances (based on the trigonometric VLBI parallax and/or CaII-method) differ from the spectrophotometric distance by a factor of 2.5. We interpret this fact as a result of presence of gray (neutral) extinction of about 1.8 mag in front of this star. The correctness of the applied spectral type/ luminosity class, Sp/L, (based on new original spectra from HARPS-N) and measurements of color indices is discussed

7

Continuous versus pulsed origination and extinction and biozones

Trammer J.

Acta Geologica Polonica

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2014

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Vol. 64, no. 4

361--366

EN

The count of biozones as an approximate measure of the origination and extinction rates of index taxa (mostly species) is proposed. The mean number of extinctions of these taxa per m.y. is 1.136 (Palaeozoic mean 0.902, Mesozoic mean 1.680, Cenozoic mean 0.789). In contrast with the majority of taxa, the originations and extinctions of index taxa, as well as of other taxa belonging to biostratigraphically important systematic groups, seems to be continuous.

8

The energy - based theory explaining dinosaur extinction and selectivity of Cretaceous - Tertiary extinction event coincided with a large meteorite impact

Gawle R., Czech Z.

International Letters of Chemistry, Physics and Astronomy

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2013

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Vol. 3

12-20

EN

This is our concise interdisciplinary energy theory explaining dinosaur extinction and the energy-based interpretation of the natural world. The theory proposes ideas which build on Luis Alvarez's impact theory by adding the energy-based mechanism underlying the mass extinction event-the final missing element to make the famous theory complete. Dinosaurs and other creatures of the Mesozoic Era differ from the commonly accepted image to which we are used.

9

The late Silurian-Middle Devonian long-term eustatic cycle as a possible control on the global generic diversity dynamics of bivalves and gastropods

Ruban Dmitry A.

Geologos

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2013

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Vol. 19, No. 3

193--200

EN

A long-term eustatic cycle (fall and subsequent rise of the global sea level) embraced the late Silurian-Middle Devonian time interval. Potentially, these sea-level changes could drive global biodiversity. The stratigraphic ranges of 204 bivalve genera and 279 gastropod genera included into the famous Sepkoski database allow reconstructing changes in the total diversity and the number of originations and extinctions of these important groups of marine benthic macro- -invertebrates during this interval. None of the recorded parameters coincided with the long-term global sea-level cycle. It cannot be not excluded, however, that the global sea-level changes did not affect the regions favourable for bivalve and gastropod radiation because of regional tectonic mechanisms; neither can it be excluded that the eustatic control persisted together with many other extrinsic and intrinsic controls. Interestingly, the generic diversity of gastropods increased together with a cooling trend, and vice versa. Additionally, the Ludlow, Eifelian, and Givetian biotic crises affected, probably, both fossil groups under study. There was also a coincidence of the relatively high bivalve generic diversity, initial radiation of gastropods and the entire biota, and the diversification of brachiopods with the Early Devonian global sea-level lowstand, and this may be interpreted as evidence of a certain eustatic control on the marine biodiversity.

10

Extinction Event Concepts for the Evolutionary Algorithms

Jaworski B., Kuczkowski Ł., Śmierzchalski R.

Przegląd Elektrotechniczny

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2012

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R. 88, nr 10b

252-255

EN

The main goal of this present paper is to propose a structure for a tool helping to determine how algorithm would react in a real live application, by checking it's adaptive capabilities in an extreme situation. Also a different idea of an additional genetic operator is being presented. As Genetic Algorithms are directly inspired by evolution, extinction events, which are elementary in our planet’s development history, became a foundation for those concepts.

PL

Celem autorów jest zaprezentowanie narzędzia, które pomoże określić możliwości adaptacyjne algorytmu ewolucyjnego poprzez sprawdzenie jego możliwości w sytuacji ekstremum. Oprócz tego, został przedstawiony pomysł dodatkowego operatora genetycznego. Obie koncepcje powstały w oparciu o zjawisko wielkiego wymierania w przyrodzie, które to stanowi ważny element w rozwoju życia na Ziemi.

11

Późnoordowickie zlodowacenie Gondwany : zapis zmian środowiskowych w sukcesji osadowej obniżenia bałtyckiego

Podhalańska T.

Prace Państwowego Instytutu Geologicznego

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2009

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T. 193

1--132

PL

Przeprowadzono badania litofacjalne, paleontologiczne i geochemiczne osadów ordowiku górnego i niższego landoweru, pochodzących ze wszystkich stref facjalnych polskiej części paleobasenu bałtyckiego. Strefy te, od skańskiej na zachodzie poprzez centralnobałtoskańską, do litewskiej na wschodzie, reprezentują przekrój środowisk sedymentacji od górnego skłonu i szelfu zewnętrznego do środowisk płytkonerytycznych szelfu wewnętrznego. Stwierdzono znaczące zmiany w środowisku abiotycznym i biotycznym związane z globalnymi zmianami paleośrodowiskowymi, wywołanymi ochłodzeniem klimatycznym i zlodowaceniem Gondwany w późnym ordowiku. Po globalnej destabilizacji ekosystemów nastąpiło ocieplenie klimatyczne, szybka transgresja i postępująca anoksja. Badania litofacjalne potwierdziły regresywny charakter osadowej sukcesji od katu do niższego hirnantu. Maksimum regresji określono na wyższą część starszego hirnantu. Początek transgresji miał miejsce w późnym hirnancie. Stwierdzono spójność zmian litofacjalnych oraz krzywych względnego poziomu morza badanego obszaru z innymi obszarami Bałtoskandii. Spójność ta implikuje, podobnie jak to jest w innych obszarach tego rejonu, że zmiany poziomu morza w późnym ordowiku mają w dużej mierze charakter zmian eustatycznych. Analiza paleontologiczna potwierdziła wpływ globalnych zmian klimatycznych i eustatycznych na przebudowę zespołów biotycznych w późnym ordowiku i wczesnym landowerze. Obecność fauny Hirnantia dokumentuje, podobnie jak w wielu innych rejonach świata, okres ochłodzenia klimatycznego i regresji; jednocześnie datując go na wczesny hirnant. Na podstawie zapisu kopalnego stwierdzono kryzys faunistyczny w późnym ordowiku oraz wyróżniono fazy ewolucyjne graptolitów, związane z późnoordowicko-wczesnosylurską przebudową zespołów. Udokumentowano współwystępowanie graptolitów i skamieniałości śladowych w strefie pogranicza ordowiku i syluru, wskazujące na stopniowo postępującą anoksję środowisk sedymentacji w okresie ocieplenia klimatycznego i transgresji w późnym hirnancie i najwcześniejszym rhuddanie. Badania geochemiczne pozwoliły na określenie zmienności składu mineralnego i chemicznego (w zakresie składników głównych i śladowych) utworów wszystkich stref facjalnych na tle abiotycznych i biotycznych zmian środowiskowych. Do analizy paleośrodowiskowej wykorzystano geochemiczne wskaźniki produktywności, ilości i pochodzenia materiału detrytycznego oraz warunków redoks. Badania te pozwoliły na rekonstrukcje warunków środowiskowych i ich zmian w czasie i przestrzeni. Przeanalizowano skład izotopowy węgla i tlenu w węglanach. Wyniki tych badań oraz porównania z obszarami sąsiednimi wykazały zgodne odchylenia wartości δ13C oraz przeważnie δ18O w kierunku wyższych wartości. Tym samym, potwierdzone zostały zmiany oceanograficzne i ekologiczne w hirnancie wiązane z okresem chłodnym i zlodowaceniem Gondwany. Wykazano, że analogiczny trend zmian izotopowych występuje na całym obszarze basenu bałtyckiego, w zgodności z danymi biostratygraficznymi, co potwierdza chronostratygraficzny potencjał uzyskanych profili izotopowych. Skorelowano wahania poziomu morza, krzywe składu izotopowego węgla i tlenu w węglanach oraz wydarzenia biotyczne w basenie bałtyckim z globalnymi zmianami środowiskowymi późnego ordowiku i wczesnego syluru. Przebudowa zespołów biotycznych i zjawiska abiotyczne zarejestrowane w osadach obniżenia bałtyckiego umożliwiają korelację z innymi obszarami Bałtyki i innych paleokontynentów. Zmiany litofacjalne, paleontologiczne i geochemiczne (w tym izotopowe), obserwowane w osadach z rozległego i zróżnicowanego facjalnie basenu bałtyckiego, stanowią ważne uzupełnienie zapisu zdarzeń późnego ordowiku i wczesnego landoweru. Przeprowadzone badania potwierdzają dużą skalę zmian środowiskowych na Bałtyce, które dobrze wiążą się z globalnymi wydarzeniami klimatycznymi, eustatycznymi i ekologicznymi.

EN

The paper deals with lithofacies, palaeontological and geochemical investigations of Upper Ordovician and lowermost Silurian deposits of all facies zones from the Polish sector of the Baltic Palaeobasin. The zones, from Scanian in the west through Central Baltoscandian to Lithuanian in the cast, represent an array of sedimentary environments from the continental slope and outer shelf to shallow-neritic environments of the inner shelf. The integrated lithofacics, palaeontological and geochemical studies supported the occurrence of changes in abiotic and biotic environments of the Upper Ordovician and lower Llandovery with regard to palacoenvironmcntal changes related to a global climatic cooling and the Gondwanan glaciation, which was followed by a warming and fast marine transgression accompanied by progressing anoxia conditions. Lithofacies studies confirmed the regressive character of the Katian and lower Hirnantian dcpositional succession. The peak regression occurred in the late early Hirnantian. The marine transgression commenced in the late Hirnantian, followed by deposition of deeper marine sediments. The uppermost Hirnantian and Rhuddanian deposits represent a new transgressive-regressive cycle. There is a coherency in the lithofacies changes between the study area and other regions of Baltoscandia. Local relative sea-level curves, constructed for Upper Ordovician and lowermost Silurian sections of the Polish part of the Baltic Depression, well correspond to the sea-level curve proposed for Baltoscandia, thus confirming the trend of relative sea-level changes throughout the Baltic Basin. Therefore, the Late Ordovician-early Llandovery relative sea-level changes in the Polish part of the Baltic Depression can be considered, like in the other regions of Baltoscandia, to have been induced largely by glacioeustatic changes. Sedimentary continuity and gradual facies and ecological changes at the Ordovician/Silurian boundary were proved in some sections in the western part of the Baltic Depression. Palaeontological analysis confirmed the influence of global climatic and custatic changes on the restructuring of biotic assemblages in Late Ordovician to early Silurian times. A faunal crisis is recorded to have occurred in Late Ordovician times. The occurrence of the Hirnantia fauna in borehole sections of both the western and eastern parts of the Baltic Depression reflects, like elsewhere in the world, a glaciocustatic sea-level drop in the early Hirnantian. The research results confirm the presence of evolutionary phases related to the Late Ordovician-early Llandovery restructuring of graptolite assemblages. Chemical composition (TOC, main and trace components) of the deposits and values of geochemical proxies show that geochemistry of the deposits from the western part of the Baltic Basin is more variable as compared to the eastern part of the study area. The docunented variations in redox conditions of the Baltic Basin well correlate with the end-Ordovician global events: better oceanic circulation and bottom water oxygenation in the early Hirnantian, and progressing transgression/anoxia accompanied by a climatic warming in the late Hirnantian and early Rhuddanian. The results of carbon and oxygen isotopic composition analysis in carbonates show a shift in δl3C and most of δ18O values towards higher values. It was proved that a similar trend of C and O isotopic composition changes occurs in| the whole Baltic Depression and, moreover, it is in conformity with biostratigraphic data. This conformity confirms that the isotopic profiles have chronostratigraphic significance. It well corresponds to the oceanographic and ecological changes observed in the Hirnantian, linked with a cool period and the Gondwanan glaciation. The results of research on carbon and oxygen isotopic composition of deposits from the Scanian facies zone arc the first results obtained from deposits of the distal shelf of Baltica. The research results were the basis for correlations of the relative sea-level changes, carbon and oxygen isotopic composition curves in carbonates, and biotic events in the Baltic Basin with global environmental changes of Late Ordovician and early Llandovery times. Thus, the results proved the influence of Late Ordovician climatic fluctuation (climatic cooling and Gondwanan glaciation followed by a climate warming), and related eustatic and ecological changes on the facies, palaeontological and geochemical record of environmental changes in the deposits of the Polish part of the Baltic Depression.

12

Photometric Study of Kepler Asteroseismic Targets

Molenda-Żakowicz J., Jerzykiewicz M., Frasca A.

Acta Astronomica

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2009

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Vol. 59, No. 2

213--237

EN

Reported are UBV and uvbyβ observations of 15 candidates for Kepler primary asteroseismic targets and 14 other stars in the Kepler field, carried out at the M.G. Fracastoro station of the Catania Astrophysical Observatory. These data serve to plot the 29 stars in two-parameter diagrams with the photometric indices (such as B-V or δm1) and the atmospheric parameters (such as the MK type or [Fe/H]) as coordinates. The two-parameter diagrams show no evidence of interstellar reddening. The photometric indices B-V and β are then used to derive photometric effective temperatures, Teff(B-V) and Teff(β). For Teff(B-V)>6400 K, the photometric effective temperatures turn out to be systematically higher than spectroscopic effective temperatures by 311±34 K and 346±91 K for Teff(B-V) and Teff(β), respectively. For Teff(B-V)<6250 K, the agreement between Teff(B-V) and the spectroscopic effective temperatures is very good. The photometric surface gravities, derived from c1 and β, show a range of about a factor of two greater than their spectroscopic counterparts do.

13

Accounting for secondary extinction in a novel X-ray absorption method used for thickness measurements of thin foils

Tomov I., Vassilev S., Tzvetkov P.

Archives of Metallurgy and Materials

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2008

|

Vol. 53, iss. 1

265-270

EN

A new approach accounting for secondary extinction (SE) is proposed for calculating the thickness of a foil mounted on textured substrate. To this end, the extinction-affected intensities of a strong substrate reflection are measured at different levels of interaction between X-radiation and crystal medium and, hence, these intensities suffer different extinction. Making use of such a series of measured intensities, the effect of extinction on the calculated foil thickness is eliminated by a proper definition of the zero-extinction condition. In this case, the definition is based on the incident-bean intensity independence of the empirical extinction coefficient k which is expressed by the measured intensities. The more precise interpretation of the experimental data leads to defining an extinction-free foil thickness, which results in improvement in the accuracy of the foil thickness determination.

PL

Zaproponowano nowe rozwiązanie dotyczące obliczeń grubości folii osadzonej na steksturyzowanym podłożu, uwzględniające ekstynkcję wtórną (SE). W tym celu, intensywność silnego odbicia dyfrakcyjnego od podłoża obarczone ekstynkcją, mierzone są przy różnych poziomach oddziaływania pomiędzy promieniami X i materiałem krystalicznym folii. Wpływ ekstynkcji na mierzoną grubość folii można wyeliminować poprzez właściwą definicję warunku zero-ekstynkcji, stosując serię zmierzonych intensywności. W takim przypadku, definicja oparta jest na niezależności intensywności wiązki pierwotnej od współczynnika doświadczalnej ekstynkcji k wyrażanego przez mierzoną intensywność. Interpretacja danych doświadczalnych prowadzi do dokładnego wyznaczenia grubości folii pozbawionej wpływu ekstynkcji.

14

Stars with ISM Polarization Observed with HPOL. III

Weitenbeck A. J.

Acta Astronomica

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2008

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Vol. 58, No. 4

433--439

EN

Polarization data are given for stars whose polarizations are mostly interstellar which were observed with the University of Wisconsin spectropolarimeter (HPOL) during 1995-2004.

15

ISM Polarization toward NGC 1502

Weitenbeck A., J., Halstead E. A., Carver A. J.

Acta Astronomica

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2008

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Vol. 58, No. 1

41--54

EN

Visual polarimetry of field stars along the line of sight to the cluster NGC 1502 and several stars in the cluster itself have been obtained. Polarization varies from much less than 1% at a distance of 100-200 pc to over 6% for the cluster stars; the field direction is uniform to within about 10° from the nearest to the most distant stars. λmax for the most distant field stars is about 5000 Å, and for the cluster stars is about 4800 Å, implying that R significantly less than 3 for this region.

16

The Triassic/Jurassic boundary in three contrasting facies in Hungary

Pálfy J., Barbacka M., Császár G., Demeny A., Görög Á., Haas J., Götz A., Oravecz-Scheffer A., Ozsvárt P., Piros O., Ruckwied K., Szeitz P., Zajzon N.

Volumina Jurassica

|

2006

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Vol. 4, no. 1

292-293

EN

Using an integrated stratigraphic approach, the Triassic/Jurassic (T/J) boundary has been studied in two different tectonostratigraphic units and three contrasting facies types in Hungary. In the northeasternmost part of the Transdanubian Range unit (part of the Alcapa terrane), the Csövár section has been intensively studied recently. Here a marine carbonate succession represents slope to basinal facies, deposited in an intraplatform basin near the margin of a Late Triassic Dachstein-type platform system. The T/J boundary is defined on the basis of ammonoid, radiolarian, conodont, and foraminiferan faunas. Paleontological data not only contribute to a biostratigraphic subdivision, but are also interpreted in the context of end-Triassic extinction and earliest Jurassic recovery of different fossil groups. A significant negative carbon isotope excursion is recorded in both carbonate and organic matter in the boundary interval. In other parts of the Transdanubian Range, a Late Triassic carbonate platform is preserved as the thick Dachstein Limestone Formation. In the Gerecse Mts. and the Tata horst, a T/J unconformity truncates the topmost Rhaetian part of the Dachstein Fm. and separates it from the overlying Hettangian strata, deposited in a deepening marine environment. Earliest Hettangian deposits and fossils are absent. A potentially more complete succession occurs farther to the west, in the Bakony Mts. Here the shallow marine carbonate deposition continues into the Hettangian, represented by the Kardosrét Limestone Fm. that overlies the Norian-Rhaetian Dachstein Fm. The lithostratigraphic boundary corresponds to the T/J boundary that marks a significant break in platform development. A disconformity and small hiatus is assumed but its duration has not yet been satisfactorily determined. A surface section on Körishegy and core material from boreholes Zt-62 (near Zirc) and Süt-28 (near Sümeg) have been investigated. The T/J boundary is marked by a sharp disappearance of Triasina hantkeni and changes in the accompanying foraminiferan and dasycladacean algal assemblage. A preliminary stable isotope study of the cores has failed to identify a negative δ ¹ ³C excursion, suggesting a hiatus at the boundary. The Mecsek Mts. in southern Hungary is part of the Tisza unit (or Tisza terrane). Here the T/J boundary falls within the coal-bearing, terrestrial to marginal marine, locally more than 1000 m thick Mecsek Formation but its precise placement has been proved difficult. Palynology offers the best potential for biostratigraphic subdivision. New palynological and paleobotanical studies are underway, aimed at a more precise palynostratigraphy and a reconstruction of climate and vegetation history in the boundary interval. In summary, the T/J boundary sections in Hungary occur in terrestrial, shallow marine (carbonate platform), and deeper marine (slope to basinal) facies. Their study provide new data towards a better understanding of the biotic and environmental changes at this critical interval of Earth history.

17

The age of the Triassic/Jurassic boundary: new data and their implications for the extinction and recovery

Pálfy J., Mundil R.

Volumina Jurassica

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2006

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Vol. 4, no. 1

294-294

EN

Providing accurate and precise radio-isotopic ages for the Triassic/Jurassic (T/J) boundary is a goal for time scale calibration but it also bears on the timing and causality of the end-Triassic mass extinction and subsequent recovery. The currently used estimate of the T/J boundary age hinges on a multi-grain zircon U-Pb age from a marine T/J boundary section in the Queen Charlotte Islands, Canada (199.6±0.4 Ma, Pálfy et al. 2000), and ⁴⁰Ar/³⁹Ar ages of volcanism of the Central Atlantic Magmatic Province (CAMP) cluster around 199.9 Ma (Knight et al. 2004), supporting a hypothesis that implicates this Large Igneous Province in triggering severe environmental changes and the biotic extinction. However, the apparent synchrony of the end-Triassic extinction and CAMP volcanism requires scrutiny for at least two reasons. Multi-grain zircon U-Pb analyses are prone to leave slight Pb loss undetected, hence producing marginally younger ages. Comparison of ⁴⁰Ar/³⁹Ar and U-Pb dates is affected by a current revision of the decay constant of ⁴⁰K and the age of fluence monitors that may require recalculation of all Phanerozoic ⁴⁰Ar/³⁹Ar ages and their upward adjustment by ˜1% (e.g. Min et al. 2000). Here we present new single-crystal zircon U-Pb ages that provide new constraints on the T/J boundary. Applying the pretreatment of thermal annealing and chemical abrasion (Mattinson 2005) resulted in a coherent cluster of zircon ages with a preliminary ²⁰⁶Pb/²³⁸U age of 198.0±0.6 Ma from a volcanic tuff layer within Early Sinemurian sediments in the Mecsek Mts., southern Hungary. The same method yielded an age of 200.6±0.3 Ma for a volcanic ash layer in ammonite-bearing Middle Hettangian marine sediments at Puale Bay, Alaska. The Early Sinemurian age provides an upper limit for the earliest Jurassic recovery interval. The two new ages suggest that the T/J boundary might be older than previously thought, likely >201 Ma. Considering the systematic bias in existing ⁴⁰Ar/³⁹Ar ages for the CAMP, synchrony of volcanism and extinction remains a strong possibility but requires further tests. Significantly, a single-crystal 206Pb/238U age of 201.3±0.3 Ma has been reported from the North Mountain basalt, a CAMP flow in Nova Scotia, Canada (Schoene et al. 2006). Further dating effort is needed to re-analyze critically important volcanic ash layers from the T/J boundary sections of the Queen Charlotte Islands.

18

Influence of regional extensional tectonics on the Jurassic ammonoid lineages as exampled on the Tethyan margins

Krishna J.

Volumina Jurassica

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2006

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Vol. 4, no. 1

180-180

EN

In another research (Krishna 2006) demonstrated the governance of the 1st and 2nd order sequence stratigraphic frameworks by regional extensional tectonics contrary to the global applicability of the eustatically driven 3rd order framework. In an effort to test the crucial role of extensional tectonics on the 1st to 2nd order sequence framework is investigated the influence of such tectonics on the Jurassic ammonoid lineages in the Tethys. The well resolved 1st to 2nd SB’s and MFS’s of the recently developed sequence framework in the Tethys are analysed vis-a-vis FAD’s and LAD’s of respective Tethyan ammonoid lineages. The lineages selected for the exercise belong to Stephanoceratacea and Perisphinctacea: – Macrocephalitinae Chrysoolithicus lineage (late Late Bathonian Triangularis Zone to mid Early Callovian Diadematus Subzone), Mayatinae (Early Oxfordian Obliqueplicatus Zone to Middle Oxfordian Orientalis Zone) of the Gondwanian Tethyan margin, and the broadly corresponding – Kosmoceratidae and – Cardioceratinae lineage of Stephanoceratacea, and – Torquatisphinctinae (late Late Oxfordian Wagurensis Zone to Early Tithonian Virgatosphinctoides Zone) – Virgatosphinctinae (late Late Kimmeridgian Infundibulum Subzone to Late Tithonian Densiplicatus Zone) of the Gondwanian Tethyan margin and the broadly corresponding – Perisphinctinae (late Late Callovian Lamberti Zone to early Late Oxfordian Bifurcatus Zone), – Ataxioceratinae (mid Late Oxfordian Bimammatum Zone to Early Kimmeridgian Hypselocyclum Zone), – Lithacoceratinae (Late Kimmeridgian Beckeri Zone to Late Tithonian Durangites Zone) of Perisphinctacea. The investigations reveal that the lineages either originate or become extinct or drastically reduced in density with marked change in evolutionary framework either at or near the 1st or 2nd order MFS’s or SB’s. For example, there is extinction of the Gondwanian Chrysoolithicus lineage at a 2nd order MFS, of the corresponding European Kosmoceratinae also at a 2nd order MFS, of the Gondwanian Mayaitinae at the 1st order MFS and of the corresponding European Cardioceratinae also at the 1st order MFS, drastic reduction in the density of the Gondwanian Torquatisphinctinae at a 2nd order MFS and origination of the corresponding European Ataxioceratinae at a 2nd order SB, of the Gondwanian Virgatosphinctinae at the 1st order MFS and of the European Lithacoceratinae near the 1st order MFS. The investigations as above explicitly demonstrate that the ranges of ammonoids lineages are controlled by the 1st and 2nd order sequence stratigraphic framework which in turn are exclusively governed by relatively low frequency high magnitude regional extensional tectonics. The regional extensional tectonics lacks globality on account of widely differing stress buildup and timing of the resultant extensional tectonic event. On the contrary the high frequency low magnitude 3rd order framework is guided by eustatic fluctuations without any interference by the low frequency high magnitude extensional tectonics.

19

Nowy sposób gaszenia łuku zakłóceniowego

Klajn A., Markiewicz H., Surówka I.

Przegląd Elektrotechniczny

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2005

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R. 81, nr 1

28-32

PL

W artykule opisano nowatorskie rozwiązanie układu do eliminacji łuku zakłóceniowego. Metoda polega na zainicjowaniu, tuż po pojawieniu się łuku zakłóceniowego, równolegle do niego przyłączonego łuku próżniowego. Wskutek znacznej różnicy mocy i energii obydwu tych wyładowań, łuk powietrzny gaśnie. Przedstawiono podstawy analizy teoretycznej oraz opisano wyniki badań laboratoryjnych, które potwierdziły skuteczność zaproponowanej metody. Badania są kontynuowane.

EN

In the paper a new method and arrangement for fault arc extinction is presented. The method consists in initiation, just after the fault arc appearance, a parallel to it connected vacuum arc. As result of the considerable difference between power and energy of both kinds of discharges, the fault arc is extinguished. The basic theoretical analysis as well as the results of laboratory experiments, which have confirm the efficiency of proposed method, are presented. lnvestigations to be continued.

20

Total to Selective Extinction Ratios and Visual Extinctions from Ultraviolet Data

Geminale A., Popowski P.

Acta Astronomica

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2004

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Vol. 54, No. 4

375--390

EN

We present determinations of the total to selective extinction ratio RV and visual extinction AV values for Milky Way stars using ultraviolet color excesses. We extend the analysis of Gnaciński and Sikorski (1999) by using non-equal weights derived from observational errors. We present a detailed discussion of various statistical errors. In addition, we estimate the level of systematic errors by considering different normalization of the extinction curve adopted by Wegner (2002). Our catalog of 782 RV and AV values and their errors is available in the electronic form on the World Wide Web.