Bodeneigenschaften und Mikrobiologie initial gebildeter Böden auf King Georges Island (Maritime Antarktis)

Die Front vieler Auslassgletscher hat sich auf King Georges Island (Maritime Antarktis) innerhalb der letzten 40 Jahre bedeutend landeinwärts verlagert. So ist der Rand des Ecology Gletschers um mehr als 500 m landeinwärts zu finden als in den 1970iger Jahren. Dies gab uns die Möglichkeit juvenile Böden zu untersuchen, die erst wenige Jahrzehnte bodenbildenden Prozessen unter periglazialen Klimabedingungen unterliegen. Wir beprobten 2014 drei Profile auf gut drainierten Standorten im Vorfeld des Ecology Gletschers und ein Bodenprofile außerhalb einer älteren Seitenmoräne. Zwei Profile (A, B), die als Hyperskeletic Cryosols (IUSS Working Group WRB, 2014) klassifiziert wurden, haben eine Vegetationsbedeckung von 0–5 % und keine erkennbare Anreicherung von SOM (Corg < 0,05 mass-%) von 0-1 cm. Profil C (Hyperskeletic Cryosol) mit etwa 80 % Vegetationsbedeckung (v.a. Usnea antarctica, Deschampsia antarctica, Colobanthus quitensis, Ochrolechia frigida) besitzt höhere N- und C-Gehalte mit N = 0,09 und Corg 1,24 mass-% sowie einen niedrigeren pH[CaCl2] mit 5,4 in 0-1 cm Tiefe; im Vergleich dazu 6,6 und 6,8 in den Profilen A und B. Während die N- und C-Gehalte mit dem höheren Bedeckungsrad erklärbar sind, ist der deutlich niedrigere pH Wert in Profil C möglicherweise insbesondere durch Zersetzung organischer Substanz und mikrobielle Aktivitäten bedingt. Profil D, ein Cambic Cryosol besitzt eine Vegetationsbedeckung von 100% und liegt im Windschatten der katabatischen Winde, die für das Gletschervorfeld bedeutsam sind. Profil C zeigt mit 3,22 mass-% Corg eine deutliche Anreicherung von SOM in 0-3 cm Tiefe (pH[CaCl2] of 4.8) und 0,24 mass-% Corg von 3-15 cm Tiefe mit pH[CaCl2]–Wert von 5,0. Während der ersten vier Jahrzehnte beeinflussen vor allem micro-topographische Unterschiede die Vegetationsbedeckung innerhalb weniger Meter auf den erst in diesem Zeitraum enteisten Flächen und können damit als Hauptfaktor für die Intensität der initialen bodenbildenden Prozesse und mikrobiologischen Aktivität betrachtet werden. Zeit - als bodenbildender Faktor – wird neben den topographischen Standortfaktoren ein weiterer Hauptfaktor nach mehr als 40 Jahren und spielt immer mehr eine Rolle auf den Flächen, die rezent vom Gletscher freigegeben wurden. Dies zeigt sich insbesondere an den mit der Tiefe gerichteten pedochemischen Ergebnissen. Die Analysen zur Abundanz, Diversität und Verbreitung der Mikroorganismen laufen derzeit und werden zur Tagung vorgestellt

Strict Forest Reserve Research in the Margin of the Carpathians, the Vár-hegy Case-Study

Sixteen forest reserves are situated in the northern part of Hungary which belongs to the Carpathian region according to EURAC delimitation (Ruffini et al. 2006). These Hungarian forest reserves expand the natural forest remnant/forest reserve net of the Carpathians towards the lower hilly region, representing the deciduous beech and oak forest belts near their lower (xeric) distribution limits. This paper outlines the Hungarian forest reserves belonging to the Carpathian region and the preliminary results of current projects in the Vár-hegy Forest Reserve (Bükk Mts., Hungary) as a case study. The alteration of tree species composition was investigated here based on the reconstruction of forest history in the previous 130 years (management period) and analyses of forest stand inventory. In another project CO2 sequestration changes of these forest stands were modeled since the clear-cutting in the 1880th and carbon stored in the forest ecosystem compartments was estimated. Our results show that the forest reserve stands are presently in a transition state from the managed forest towards a more natural mixed forest with several age-classes

Solar dynamo model with nonlocal alpha-effect

The first results of the solar dynamo model that allows for the diamagnetic effect of inhomogeneous turbulence and the nonlocal alpha-effect due to the rise of magnetic loops are discussed. The nonlocal alpha-effect is not subject to the catastrophic quenching related to the conservation of magnetic helicity. Given the diamagnetic pumping, the magnetic fields are concentrated near the base of the convection zone, although the distributed-type model covers the entire thickness of the convection zone. The magnetic cycle period, the equatorial symmetry of the field, its meridional drift, and the polar-to-toroidal field ratio obtained in the model are in agreement with observations. There is also some disagreement with observations pointing the ways of improving the model.Comment: To appear in Astronomy Letters, 10 pages, 5 figure

The model of dynamo with small number of modes and magnetic activity of T Tauri stars

The model that describes operation of dynamo in fully convective stars is presented. It is based on representation of stellar magnetic field as a superposition of finite number of poloidal and toroidal free damping modes. In the frame of adopted low of stellar differential rotation we estimated minimal value of dynamo number D, starting from which generation of cyclic magnetic field in stars without radiative core is possible. We also derived expression for period of the cycle. It was found that dynamo cycles of fully convective stars and stars with thin convective envelopes differ in a qualitative way: 1) distribution of spots over latitude during the cycle is different in these stars; 2) the model predicts that spot formation in fully convective stars should be strongly suppressed at some phases of the cycle. We have analyzed historical lightcurve of WTTS star V410 Tau and found that long term activity of the star is not periodic process. Rather one can speak about quasi cyclic activity with characteristic time of $\sim 4$ yr and chaotic component over imposed. We concluded also that redistribution of cool spots over longitude is the reason of long term variations of V410 Tau brightness. It means that one can not compare directly results of photometric observations with predictions of our axially symmetric (for simplicity) model which allows to investigate time evolution of spot's distribution over latitude. We then discuss what kind of observations and in which way could be used to check predictions of the dynamo theory.Comment: 18 pages, 5 figures, accepted to Astron. Let

Convection and Retro-Convection Enhanced Delivery: Some Theoretical Considerations Related to Drug Targeting

Delivery of drugs and macromolecules into the brain is a challenging problem, due in part to the blood–brain barrier. In this article, we focus on the possibilities and limitations of two infusion techniques devised to bypass the blood–brain barrier: convection enhanced delivery (CED) and retro-convection enhanced delivery (R-CED). CED infuses fluid directly into the interstitial space of brain or tumor, whereas R-CED removes fluid from the interstitial space, which results in the transfer of drugs from the vascular compartment into the brain or tumor. Both techniques have shown promising results for the delivery of drugs into large volumes of tissue. Theoretical approaches of varying complexity have been developed to better understand and predict brain interstitial pressures and drug distribution for these techniques. These theoretical models of flow and diffusion can only be solved explicitly in simple geometries, and spherical symmetry is usually assumed for CED, while axial symmetry has been assumed for R-CED. This perspective summarizes features of these models and provides physical arguments and numerical simulations to support the notion that spherical symmetry is a reasonable approximation for modeling CED and R-CED. We also explore the potential of multi-catheter arrays for delivering and compartmentalizing drugs using CED and R-CED

Therapeutic Potential of Adipose-Derived Therapeutic Factor Concentrate for Treating Critical Limb Ischemia

Transplantation of adipose-derived stem cells (ADSCs) is an emerging therapeutic option for addressing intractable diseases such as critical limb ischemia (CLI). Evidence suggests that therapeutic effects of ADSCs are primarily mediated through paracrine mechanisms rather than transdifferentiation. These secreted factors can be captured in conditioned medium (CM) and concentrated to prepare a therapeutic factor concentrate (TFC) composed of a cocktail of beneficial growth factors and cytokines that individually and in combination demonstrate disease-modifying effects. The ability of a TFC to promote reperfusion in a rabbit model of CLI was evaluated. A total of 27 adult female rabbits underwent surgery to induce ischemia in the left hindlimb. An additional five rabbits served as sham controls. One week after surgery, the ischemic limbs received intramuscular injections of either (1) placebo (control medium), (2) a low dose of TFC, or (3) a high dose of TFC. Limb perfusion was serially assessed with a Doppler probe. Blood samples were analyzed for growth factors and cytokines. Tissue was harvested postmortem on day 35 and assessed for capillary density by immunohistochemistry. At 1 month after treatment, tissue perfusion in ischemic limbs treated with a high dose of TFC was almost double (p < 0.05) that of the placebo group [58.8 ± 23 relative perfusion units (RPU) vs. 30.7 ± 13.6 RPU; mean ± SD]. This effect was correlated with greater capillary density in the affected tissues and with transiently higher serum levels of the angiogenic and prosurvival factors vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF). The conclusions from this study are that a single bolus administration of TFC demonstrated robust effects for promoting tissue reperfusion in a rabbit model of CLI and that a possible mechanism of revascularization was promotion of angiogenesis by TFC. Results of this study demonstrate that TFC represents a potent therapeutic cocktail for patients with CLI, many of whom are at risk for amputation of the affected limb

Meritocratic aspects concerning civil servant career: comparative study in Central and Eastern European countries

Central and Eastern Europe has known in the last 20 years profound changes. The shift from a dictatorial system to a democratic system forced the states from this area to adopt structural measures for all public institutions. In this context, the institution of "civil servant" could not remain unaffected. In the period of communist regimes, the institution of "civil servant" did not exist, the civil servant being just a simple employee of the state. Work relations were the same as for any employee. The shift to another political system, the democratic one, determined the reconsideration the role and the place of public administration, and implicit of civil servant in the framework of the state system. In this context, it has been a shift from the statute of simple employee to that of civil servant, representing the power of the state. In the process of accession to the European Union, the states from Central and Eastern Europe have been permanently pressured to clearly define a strategy concerning the competitiveness of public administration, concerning the statute and the career of civil servant. In the context of democratisation, we can notice that the principle of meritocracy has become a key principle in the civil servant's career. The term "meritocracy" is often used in order to describe a type of society in which wealth and social position are obtained mainly through competition or through ability or proved competences. A position invested with responsibilities and social prestige has to be acquired and not inherited or obtained by arbitrary criteria. Meritocracy represents also the term used to describe or to criticise a society in competition that accepts inequitable disparities of income, wealth and social position. Taking into account the above considerations, the present paper aims to achieve an analysis of meritocratic aspects in the systems of planning and promotion of civil servant's career in Central and Eastern Europe