scholarly journals Insight into volcanic garnet: origin and significance of garnet as exemplified by a detailed petro-mineralogical study of the Breziny andesite (Central Slovakia Volcanic Field, Western Carpathians, Central Europe)

Volcanica ◽  
2021 ◽  
pp. 149-187
Author(s):  
Jacky Bouloton

Almandine-rich garnets from a Neogene andesite of Slovakia can be divided into two main types. Garnet megacrysts are magmatic and form a chemically homogeneous group that contains, on average, about 5 wt% CaO and 4.5 wt% MgO as petrogenetically significant components. Garnets occurring in lithic fragments and garnets aggregated in garnetite lenses are characterised by Ca-poor cores (CaO <= 2 wt%) that testify for a two-step history and correspond respectively to inherited pre-anatectic and peritectic garnets. Available experimental data show that the composition of magmatic garnet megacrysts is compatible with a peritectic origin, through the fluid-absent melting of an immature metasedimentary protolith or a tonalitic gneiss. However, thermal evolution evidenced by zircons shielded in garnet rather suggests that garnet nucleated and grew by cooling of a hybrid magma pool, resulting from the complete mixing of crust- and mantle-derived melts.

2016 ◽  
Vol 8 (3) ◽  
pp. 5
Author(s):  
Jirí Stavek

<p class="1Body">An attempt is presented for the description of the spectral colors using the standard trigonometric tools in order to extract more information about photons. We have arranged the spectral colors on an arc of the circle with the radius R = 1 and the central angle θ = π/3 when we have defined cos (θ) = λ<sub>380</sub>/λ<sub>760</sub> = 0.5. Several trigonometric operations were applied in order to find the gravity centers for the scotopic, photopic, and mesopic visions. The concept of the center of gravity of colors introduced Isaac Newton. We have postulated properties of the long-lived photons with the new interpretation of the Hubble (Zwicky-Nernst) constant H<sub>0</sub> = 2.748… * 10<sup>-18</sup> kg kg<sup>-1 </sup>s<sup>-1</sup>, the specific mass evaporation rate (SMER) of gravitons from the source mass. The stability of international prototypes of kilogram has been regularly checked. We predict that those standard kilograms due to the evaporation of gravitons lost 8.67 μg kg<sup>-1</sup> century<sup>-1</sup>. The energy of long-lived photons was trigonometrically decomposed into three parts that could be experimentally tested: longitudinal energy, transverse energy and energy of evaporated gravitons. We tested the properties of the long-lived photons with the experimental data published for the best available standard candles: supernovae Type Ia. There was found a surprising match of those experimental data with the model of the long-lived photons. Finally, we have proposed a possible decomposition of the big G (Newtonian gravitational constant) and the small kappa κ (Einsteinian gravitational constant) in order to get a new insight into the mysterious gravitational force and/or the curvature concept.</p>


2017 ◽  
Vol 57 (3) ◽  
Author(s):  
Lili Zách

ABSTRACTIn the aftermath of the Great War, the birth of new independent small states in East-Central Europe was closely followed in Irish nationalist circles due to the possibility of Partition in Ireland. Newspaper editorials, journal articles and diplomatic accounts illustrate that post-war Ireland had an open attitude toward the settlement of borders on the Continent as the dissolution of the Austro-Hungarian Empire was similarly controversial. This paper aims to investigate how contemporary Irish commentators perceived the question of boundary settlements in Central Europe in order to provide an insight into the transformation of political space in both Ireland and Central Europe. After providing a brief background to the Irish boundary question, this paper touches upon the most important points in historiography with regard to border settlements in the post-World War I era.. It also discusses Irish Partition history in detail, concentrating on the North-Eastern Boundary Bureau (NEBB) and the Boundary Commission, and the importance of Central European precedents in their work. Moreover, this paper also proposes to provide an insight into the Irish interest in the minority problem in European borderland regions after 1925 in order to illustrate the outward-looking attitude to Irish nationalists, even in relation to borders and minorities.


2018 ◽  
Author(s):  
Minryung R. Song ◽  
Sang Wan Lee

AbstractDopamine activity may transition between two patterns: phasic responses to reward-predicting cues and ramping activity arising when an agent approaches the reward. However, when and why dopamine activity transitions between these modes is not understood. We hypothesize that the transition between ramping and phasic patterns reflects resource allocation which addresses the task dimensionality problem during reinforcement learning (RL). By parsimoniously modifying a standard temporal difference (TD) learning model to accommodate a mixed presentation of both experimental and environmental stimuli, we simulated dopamine transitions and compared it with experimental data from four different studies. The results suggested that dopamine transitions from ramping to phasic patterns as the agent narrows down candidate stimuli for the task; the opposite occurs when the agent needs to re-learn candidate stimuli due to a value change. These results lend insight into how dopamine deals with the tradeoff between cognitive resource and task dimensionality during RL.


2020 ◽  
Vol 80 (1) ◽  
Author(s):  
Slobodan Jovanović ◽  
Milan Glišić

In the last two decades, the number of research articles with a focus on urban ecosystems in Europe has increased significantly. However, explored cities are very unevenly distributed, and most of the studies are focused on Central Europe. The aim of this analysis was to provide a realistic insight into the results of previous research on urban flora and vegetation in Southeast Europe. The analysis covers a total of 149 articles, which are classified according to the topic and concept of research. The rates of exploration of urban flora and vegetation vary considerably across the countries of Southeast Europe. The floristic approach was the most common in most of the countries. Although some countries of Southeast Europe have a significant number of floristic studies (e.g. Serbia and Croatia with more than 20 of each country), their urban flora is still insufficiently explored compared to other European regions. Also, the use of different methodologies makes it impossible to compare results in an adequate way and draw relevant conclusions. Unlike the studies in most of Europe, with a broader spatial framework and uniform methodology, in Southeast Europe they usually referred to individual cities, specific habitats or certain parts of the cities. Hence, including Southeast Europe in large-scale studies would be beneficial.


Geomorphology ◽  
2020 ◽  
Vol 364 ◽  
pp. 107248 ◽  
Author(s):  
Tomáš Pánek ◽  
Jozef Minár ◽  
Ladislav Vitovič ◽  
Michal Břežný

Author(s):  
D R Absolom ◽  
W Zingg ◽  
A W Neumann ◽  
C J van Oss

It has been suggested that platelet phagocytosis might be a useful model to provide insight into platelet adhesion to polymer substrates commonly employed in biocompatibility studies. To test this supposition the present study of platelet engulfment of four strains of bacteria (opsonized as well as non-opsonized) under well defined in vitro physical conditions was undertaken. In physiologic conditions, platelet adhesion is maximum on the more hydrophilic polymers and minimum on the more hydrophobic surfaces; bacterial engulfment under the same conditions follows an identical pattern in that the more hydrophilic bacteria are more readily engulfed. The experimental data further suggest that, unlike phagocytosis by neutrophils platelet interaction with bacteria is non-specific in that it does not appear to be antibody receptor modulated. Opsonization of the bacteria does however play an important role in that it serves to increase the hydrophobicity of the bacteria thereby influencing the degree of bacterial engulfment. A striking correlation between the extent of bacterial engulfment and the Helmholtz Free Energy of Engulfment exists. Platelet adhesion to polymer substrates and platelet engulfment of bacteria appear to follow the same thermodynamic model.


2002 ◽  
Vol 283 (5) ◽  
pp. E1084-E1101 ◽  
Author(s):  
Ahmad R. Sedaghat ◽  
Arthur Sherman ◽  
Michael J. Quon

We develop a mathematical model that explicitly represents many of the known signaling components mediating translocation of the insulin-responsive glucose transporter GLUT4 to gain insight into the complexities of metabolic insulin signaling pathways. A novel mechanistic model of postreceptor events including phosphorylation of insulin receptor substrate-1, activation of phosphatidylinositol 3-kinase, and subsequent activation of downstream kinases Akt and protein kinase C-ζ is coupled with previously validated subsystem models of insulin receptor binding, receptor recycling, and GLUT4 translocation. A system of differential equations is defined by the structure of the model. Rate constants and model parameters are constrained by published experimental data. Model simulations of insulin dose-response experiments agree with published experimental data and also generate expected qualitative behaviors such as sequential signal amplification and increased sensitivity of downstream components. We examined the consequences of incorporating feedback pathways as well as representing pathological conditions, such as increased levels of protein tyrosine phosphatases, to illustrate the utility of our model for exploring molecular mechanisms. We conclude that mathematical modeling of signal transduction pathways is a useful approach for gaining insight into the complexities of metabolic insulin signaling.


Zootaxa ◽  
2017 ◽  
Vol 4238 (4) ◽  
pp. 597 ◽  
Author(s):  
FABIO CIANFERONI ◽  
MARGHERITA NORBIATO ◽  
MARCO DOGLIOTTI

Salda henschii (Reuter, 1891) is a boreo-montane species of Saldidae (Hemiptera: Heteroptera) restricted to mountain bogs and streams in central Europe (e.g., Western Carpathians, Alps) and to freshwater wetlands in lowland coastal areas in northern Europe (Fennoscandia); it is a vicariant of the arctic (Holarctic) element S. sahlbergi Reuter, 1875 (Hoberlandt 1977; Schuh et al. 1987; Péricart 1990; Lindskog 1991; Vinokurov 2010). 


Sign in / Sign up

Export Citation Format

Share Document