Determination of the Lithosphere-Asthenosphere Boundary (LAB) beneath the Nógrád-Gömör Volcanic Field by combined geophysical (magnetotellurics) and geochemical methods

Understanding the fundamental role of LAB is substantial for the investigation of the geodynamic evolution of the Earth. The LAB depths can be estimated by different geophysical methods (seismology, magnetotellurics), however these depths are controversial. It has been emphasized in the literature that combined geophysical and geochemical approach may lead to better understanding of these depths. The magnetotellurics (MT) is very powerful method because it indicates the sudden increase in conductivity at the LAB. The mantle xenoliths (small fragments of the lithospheric mantle) provide the information to reconstruct their P-T paths. In the Carpathian-Pannon region (CPR) five, well-studied occurrences of mantle xenoliths-bearing Plio-Pleistocene alkali basalts are known, which makes the CPR a very promising area for investigating the inconsistency in the LAB estimates. As a test area Nógrád-Gömör Volcanic Field (NGVF) has been chosen. The host basalt erupted at the NGVF collected mantle xenoliths from a small volume of the upper mantle in a depth of about 40-50 km. The major element geochemistry of the studied xenoliths indicates that most of them represent common lherzolitic mantle, whereas others show strong wehrlitisation process. This metasomatism is supposed to be caused by a migrating mafic melt agent, resulting in the transformation of a large portion of lherzolite to wehrlite beneath the NGVF, possibly just below the crust mantle boundary. In aim to detect the LAB at the research area and find the correlation with petrologic and geochemical results we carried out MT deep soundings. The campaign contained 12 long period MT stations with 3-5 km average spacing along 60 km long profile SSE to NNW direction. This presentation summarizes the preliminary results of the combined geophysical and geochemical approaches to determine the LAB depths

Rekurzív sorozatok és diofantoszi problémák = Recursive sequences and Diophantine problems

A 2005-2008-as periódusban, azaz az OTKA 4 éve alatt a kutatócsoportunk a szerződésben vállalt témák kutatásával foglalkozott. Így, tanulmányoztuk a polinomiális-exponenciális diofantikus egyenleteket, a lineáris rekurziókat, a balansz számokat, az unimodális sorozatokat és a lineáris rekurziókhoz kapcsolódó polinomsorzatok polinomjai gyökeit és azok lokalizációját. A kutatócsoport létszáma végig 5 fő volt (témavezető: Mátyás Ferenc PhD; tagok: Liptai Kálmán PhD, Szalay László PhD, Olajos Péter PhD és Orosz Gyuláné PhD. Az OTKA támogatásával írtunk 20 cikket, ebből már megjelent 16 és további 4 van megjelenés alatt, tönbb rangos nemzetközi számelméleti konferencián tarthattunk előadásokat kutatási eredményeinkből. A megtartott (hazai és külföldi) konferencia-előadásaink száma 27. Az OTKA csoportunk nemzetközi számelméleti konferenciát szervezett Egerben (2007) és Sopronban (2008). Részt vettünk továbbá az Explicit Methods in Number Theory (Bordeaux, 2007) és a Winter School on Explicit Methods in Number Theory (Debrecen, 2009. január) workshop-okon. Összefoglalva elmondható, hogy az OTKA támogatást a terveknek megfelelően használtuk, az elért eredményeink a jövőre nézve is biztatóak. | In the period 2005-2008 the research team delt with the polynomial-exponential Diophantine equations, linear recurreces, balancing numbers, unimodular sequences and estimations of the absoluta values of zeros of polynomials whose the coefficients belong to given binary linear recursive sequences of integers. The research team had 5 members, namely Ferenc Mátyás PhD (teamleader), Kálmán Liptai PhD, László Szalay PhD, Péter Olajos PhD and Mrs. Gyuláné Orosz PhD. We have written 21 scientific papers and we have held 27 conference lectures on international conferences of number theory. We also took part in the work of two workshops, these were: Explicit Methods in Number Theory (Bordeaux, 2007) and Winter School on Explicit Methods in Number Theory (Debrecen, 2009, January). Summarizing, we can say that our research work was succesfull and we can belive in a similar continuation

Does turbulence determine the initial mass function?

Published onlineThis is the author accepted manuscript. The final version is available from Oxford University Press via the DOI in this record.We test the hypothesis that the initial mass function (IMF) is determined by the density probability distribution function (PDF) produced by supersonic turbulence. We compare 14 simulations of star cluster formation in 50 M molecular cloud cores where the initial turbulence contains either purely solenoidal or purely compressive modes, in each case resolving fragmentation to the opacity limit to determine the resultant IMF. We find statistically indistinguishable IMFs between the two sets of calculations, despite a factor of 2 difference in the star formation rate and in the standard deviation of log (ρ). This suggests that the density PDF, while determining the star formation rate, is not the primary driver of the IMF.We thank the anonymous referee for comments which have improved the paper. We acknowledge CPU time on gSTAR, funded by Swinburne University and the Australian Government. This project was funded via Australian Research Council Discovery Project DP130102078 and Future Fellowship FT130100034. We used SPLASH (Price 2007)