Isotopic studies on ore potential granitoid rocks in the Häme belt, Finland

2020 ◽  
Author(s):  
Matti Kurhila ◽  
Markku Tiainen ◽  
Hannu Huhma ◽  
Hannu Mäkitie
Keyword(s):  
Isotope Analysis ◽  
Shear Zones ◽  
Hydrothermal Activity ◽  
Published Data ◽  
Main Stage ◽  
Granitoid Magmatism ◽  
Rapid Sequence ◽  
Wide Range ◽  
Granitoid Rocks ◽  
Simultaneous Existence

<p>The Häme belt in southwestern Finland hosts several types of ore formations. Among others, Cu, Au, W, Li and La mineralizations have been identified. These mineralizations are linked with various types of granitoid rocks within the Paleoproterozoic Svecofennian bedrock. We have studied the granitoids and equivalent hypabyssal rocks by whole-rock geochemistry, U-Pb zircon geochronology and Sm-Nd isotope analysis. Geochemically, the granitoids show a wide range from adakitic to arc-type, implying that they had different source environments. New age data show that different types of granitoids (tonalitic, leucogranitic, granodioritic etc.) were emplaced simultaneously: the samples have ages from 1888 Ma to 1883 Ma and are coeval within the error limits. Nd isotopic results show slightly depleted compositions with initial epsilon values around +1, in line with most of the previously published data. An exception is the Cu-Au bearing Arolanmäki granite, which indicates a juvenile origin with an initial epsilon value of +3.2.</p><p><br>Overall the sources of granitoid magmatism vary considerably, and the overlapping ages indicate either a very rapid sequence or a simultaneous existence of varying types of magmatism. The ages coincide with the main stage of the Svecofenniean orogeny in the area. Later tectonic and hydrothermal activity is demonstrated by <1.80 Ga monazite and titanite ages as well as pegmatites. The granitoid magmatism of the Häme belt is related to several types of ore forming processes. The 1.88 Ga granitoids are hosting Cu-Au and W-Au-deposits, some of them interpreted as porphyric type deposits. The 1.80 Ga pegmatites include several LCT pegmatites hosting Li-deposits. The orogenic gold deposist of the Jokisivu-type in Häme belt have been interpreted to be controlled by the shear zones related to the 1.80 Ga granitoid magmatism. </p>

scholarly journals Sinistral transpression and hydrothermal activity during emplacement of the Early Proterozoic Julianehåb batholith, Ketilidian orogenic belt, South Greenland

1994 ◽  
Vol 163 ◽  
pp. 5-22
Author(s):  
B Chadwick ◽  
P Erfurt ◽  
T Frisch ◽  
R.A Frith ◽  
A.A Garde ◽  
...  
Keyword(s):  
Shear Zones ◽  
Field Work ◽  
Hydrothermal Activity ◽  
Vertical Shear ◽  
Early Proterozoic ◽  
North West ◽  
North East ◽  
The North ◽  
Granitoid Rocks ◽  
Quartz Veining

The first systematic investigations of the central part of the Early Proterozoic Ketilidian orogen in the vicinity of Søndre Sermilik in the early 1960s suggested that this part of the orogen comprised a mixture of the Julianehåb granite, altered supracrustal rocks and older orthogneisses. Recent field work has shown that the area consists only of a variably deformed suite of granitic to dioritic plutonic rocks and a range of hornblende-bearing dykes of the appinite suite which all belong to the Julianehåb batholith. Steep to vertical shear zones with widths from a few centimetres to more than one kilometre are a significant element of the structure. The principal shear zones trend north-east and they are parallel to the schistosity and subhorizontal linear structures in the granitoid rocks. Kinematic indicators in many of the shear zones indicate sinistral transcurrent displacements. The relationships between granite fabrics, shear zones and mafic dykes suggest that the Julianehåb batholith was emplaced during subduction from the south towards the Archaean craton in the north-west in a sinistral transpressional system. Effects of hydrothermal alteration, mainly in the form of quartz veining, silicification, chloritisation, epidotisation and pyritisation, are common within and adjacent to the largest shear zones. These effects are believed to be related to late stages of the evolution of the batholith. Gold anomalies appear to be closely tied to the hydrothermal phenomena.

It is better an approximate answer to the right question than the exact answer to the wrong question : the case of the psychometric analysis of the ASQ:SE

2020 ◽  
Author(s):  
Luis Anunciacao ◽  
janet squires ◽  
J. Landeira-Fernandez
Keyword(s):  
Internal Structure ◽  
Statistical Methods ◽  
Principal Component ◽  
Psychological Theory ◽  
Published Data ◽  
Multivariate Statistical ◽  
Exact Answer ◽  
Wide Range ◽  
Ages And Stages Questionnaire ◽  
The Right

One of the main activities in psychometrics is to analyze the internal structure of a test. Multivariate statistical methods, including Exploratory Factor analysis (EFA) and Principal Component Analysis (PCA) are frequently used to do this, but the growth of Network Analysis (NA) places this method as a promising candidate. The results obtained by these methods are of valuable interest, as they not only produce evidence to explore if the test is measuring its intended construct, but also to deal with the substantive theory that motivated the test development. However, these different statistical methods come up with different answers, providing the basis for different analytical and theoretical strategies when one needs to choose a solution. In this study, we took advantage of a large volume of published data (n = 22,331) obtained by the Ages and Stages Questionnaire Social-Emotional (ASQ:SE), and formed a subset of 500 children to present and discuss alternative psychometric solutions to its internal structure, and also to its subjacent theory. The analyses were based on a polychoric matrix, the number of factors to retain followed several well-known rules of thumb, and a wide range of exploratory methods was fitted to the data, including EFA, PCA, and NA. The statistical outcomes were divergent, varying from 1 to 6 domains, allowing a flexible interpretation of the results. We argue that the use of statistical methods in the absence of a well-grounded psychological theory has limited applications, despite its appeal. All data and codes are available at https://osf.io/z6gwv/.

scholarly journals Regulation of Cytochrome c Oxidase by Natural Compounds Resveratrol, (–)-Epicatechin, and Betaine

Cells ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1346
Author(s):  
Icksoo Lee
Keyword(s):  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
Model Systems ◽  
Health Improvement ◽  
Published Data ◽  
Mitochondrial Electron Transport Chain ◽  
Naturally Occurring ◽  
Transport Chain ◽  
Wide Range ◽  
Experimental Model Systems

Numerous naturally occurring molecules have been studied for their beneficial health effects. Many compounds have received considerable attention for their potential medical uses. Among them, several substances have been found to improve mitochondrial function. This review focuses on resveratrol, (–)-epicatechin, and betaine and summarizes the published data pertaining to their effects on cytochrome c oxidase (COX) which is the terminal enzyme of the mitochondrial electron transport chain and is considered to play an important role in the regulation of mitochondrial respiration. In a variety of experimental model systems, these compounds have been shown to improve mitochondrial biogenesis in addition to increased COX amount and/or its enzymatic activity. Given that they are inexpensive, safe in a wide range of concentrations, and effectively improve mitochondrial and COX function, these compounds could be attractive enough for possible therapeutic or health improvement strategies.

Lateral skull base surgery: a complicated pursuit?

2007 ◽  
Vol 122 (3) ◽  
pp. 221-229
Author(s):  
V C Cousins
Keyword(s):  
Skull Base ◽  
Skull Base Surgery ◽  
Treatment Modalities ◽  
Published Data ◽  
Know How ◽  
Team Assessment ◽  
Pathological Conditions ◽  
Lateral Skull Base ◽  
Wide Range ◽  
Multi Disciplinary Team

AbstractThe management of lesions of the lateral skull base is a highly sophisticated branch of surgery generally performed by otolaryngology–head and neck surgeons as part of a multi-disciplinary team. Assessment of patients with diseases affecting the lateral skull base can be complex, as can the application of the various treatment modalities and the management of the expected and unexpected side effects of that treatment.A wide range of pathological conditions occur in the lateral skull base. Many operations and procedures have been described for dealing with them. There is not necessarily one correct solution to the management of any particular problem in the skull base, with multiple factors to be considered in planning and intervention.As surgeons, we need to know how our own results and outcomes compare with pooled, published data concerning the implications and complications occurring as a result of intervention, in order to better advise our patients on their management.

The petrological and geochemical study of granitoid rocks from Mashhad area, Iran: Evidence for the Late Triassic Collisional Belt Northeast of Iran

2021 ◽  
Author(s):  
Banafsheh Vahdati ◽  
Seyed Ahmad Mazaheri
Keyword(s):  
Subduction Zones ◽  
Tectonic Setting ◽  
Crustal Contamination ◽  
Oceanic Lithosphere ◽  
Late Triassic ◽  
Common Belief ◽  
Thrust Tectonics ◽  
Wide Range ◽  
Lree Enrichment ◽  
Granitoid Rocks

<p>Mashhad granitoid complex is part of the northern slope of the Binalood Structural Zone (BSZ), Northeast of Iran, which is composed of granitoids and metamorphic rocks. This research presents new petrological and geochemical whole-rock major and trace elements analyses in order to determine the origin of granitoid rocks from Mashhad area. Field and petrographic observations indicate that these granitoid rocks have a wide range of lithological compositions and they are categorized into intermediate to felsic intrusive rocks (SiO<sub>2</sub>: 57.62-74.39 Wt.%). Qartzdiorite, tonalite, granodiorite and monzogranite are common granitoids with intrusive pegmatite and aplitic dikes and veins intruding them. Based on geochemical analyses, the granitoid rocks are calc-alkaline in nature and they are mostly peraluminous. On geochemical variation diagrams (major and minor oxides versus silica) Na<sub>2</sub>O and K<sub>2</sub>O show a positive correlation with silica while Al<sub>2</sub>O<sub>3</sub>, TiO<sub>2</sub>, CaO, Fe<sub>2</sub>O<sub>3</sub>, and MgO show a negative trend. Therefore fractional crystallization played a considerable role in the evolution of Mashhad granitoids. Based on the spider diagrams, there are enrichments in LILE and depletion in HFSE. Low degrees of melting or crustal contamination may be responsible for LILE enrichment. Elements such as Pb, Sm, Dy and Rb are enriched, while Ba, Sr, Nd, Zr, P, Ti and Yb (in monzogranites) are all depleted. LREE enrichment and HREE depletion are observed in all samples on the Chondrite-normalized REE diagram. Similar trends may be evidence for the granitoids to have the same origin. Besides, LREE enrichment relative to HREE in some samples can indicate the presence of garnet in their source rock. Negative anomalies of Eu and Yb are observed in monzogranites. Our results show that Mashhad granitoid rocks are orogenic related and tectonic discrimination diagrams mostly indicate its syn-to-post collisional tectonic setting. No negative Nb anomaly compared with MORB seems to be an indication of non-subduction zone related magma formation. According to the theory of thrust tectonics of the Binalood region, the oceanic lithosphere of the Palo-Tethys has subducted under the Turan microplate. Since the Mashhad granitoid outcrops are settled on the Iranian plate, this is far from common belief that these granitoid rocks are related to the subduction zones and the continental arcs. The western Mashhad granitoids show more mafic characteristics and are possibly crystallized from a magma with sedimentary and igneous origin. Thus, Western granitoid outcrops in Mashhad are probably hybrid type and other granitoid rocks, S and SE Mashhad are S-type. Evidences suggest that these continental collision granitoid rocks are associated with the late stages of the collision between the Iranian and the Turan microplates during the Paleo-Tethys Ocean closure which occurred in the Late Triassic.</p>

Long-term Aptian marine osmium isotopic record of Ontong Java Nui activity

Geology ◽  
2021 ◽  
Author(s):  
Hironao Matsumoto ◽  
Rodolfo Coccioni ◽  
Fabrizio Frontalini ◽  
Kotaro Shirai ◽  
Luigi Jovane ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Volcanic Eruptions ◽  
Hydrothermal Activity ◽  
Published Data ◽  
Isotopic Data ◽  
Oceanic Plateaus ◽  
Carbon Burial ◽  
Organic Carbon Burial ◽  
Isotopic Records

The early to mid-Aptian was punctuated by episodic phases of organic-carbon burial in various oceanographic settings, which are possibly related to massive volcanism associated with the emplacement of the Ontong Java, Manihiki, and Hikurangi oceanic plateaus in the southwestern Pacific Ocean, inferred to have formed a single plateau called Ontong Java Nui. Sedimentary osmium (Os) isotopic compositions are one of the best proxies for determining the timing of voluminous submarine volcanic episodes. However, available Os isotopic records during the age are limited to a narrow interval in the earliest Aptian, which is insufficient for the reconstruction of long-term hydrothermal activity. We document the early to mid-Aptian Os isotopic record using pelagic Tethyan sediments deposited in the Poggio le Guaine (Umbria-Marche Basin, Italy) to precisely constrain the timing of massive volcanic episodes and to assess their impact on the marine environment. Our new Os isotopic data reveal three shifts to unradiogenic values, two of which correspond to black shale horizons in the lower to mid-Aptian, namely the Wezel (herein named) and Fallot Levels. These Os isotopic excursions are ascribed to massive inputs of unradiogenic Os to the ocean through hydrothermal activity. Combining the new Os isotopic record with published data from the lowermost Aptian organic-rich interval in the Gorgo a Cerbara section of the Umbria-Marche Basin, it can be inferred that Ontong Java Nui volcanic eruptions persisted for ~5 m.y. during the early to mid-Aptian.

Effects of Buoyancy on Laminar Flow in Curved Elliptic Ducts

1992 ◽  
Vol 114 (4) ◽  
pp. 936-943 ◽  
Author(s):  
Z. F. Dong ◽  
M. A. Ebadian
Keyword(s):  
Laminar Flow ◽  
Stokes Equations ◽  
Control Volume ◽  
Boussinesq Approximation ◽  
Navier Stokes ◽  
Uniform Heat Flux ◽  
Published Data ◽  
Circular Duct ◽  
Uniform Wall Temperature ◽  
Wide Range

This paper numerically investigates the effects of buoyancy on fully developed laminar flow in a curved duct with an elliptic cross section. The flow of Newtonian fluids is assumed steady in terms of Boussinesq approximation. The curved elliptic duct is subjected to thermal boundary conditions of axially uniform heat flux and peripherally uniform wall temperature. The numerically generated boundary-fitted coordinate system is applied to discretize the solution domain of the elliptic duct, and the Navier-Stokes equations and the energy equation, including the curvature ratio, are solved by use of the control volume-based finite difference method. The solution covers a wide range of curvature ratios, and Dean and Grashof numbers. The results presented are displayed graphically and in tabular form to illustrate the buoyancy effect. It is further shown that buoyancy acts to increase both the Nusselt number and the friction factor and changes the distribution of the velocity and the temperature. The results for the curved circular duct with and without buoyancy are compared with the data available in the open literature for all cases. Also compared with the published data are the results of laminar flow in a curved elliptic duct, and very good agreement is obtained.

greater the probability that the particles will miss the high shear zones on a single pass through the device. For this reason the discharge of many rotor/stator devices is re-stricted with a series of holes or bars, or with a grid, which performs two separate tasks. First, a discharge grid absolutely limits the maximum particle size that can exit the mixer. If the holes on the discharge grid are 2 mm, it is virtually impossible for par-ticles larger than that diameter to pass through the machine. Rotor/stator in-line mix-ers are made with restricting grids as small as 0.5 mm, and a wide range of larger sizes up to 50 mm or even unrestricted outlets. A sample of such grids is presented in Fig. 29. But even the smallest usable discharge grid does not necessarily provide abso-lute control of the required size distributions in the range of fine dispersion. This is the second reason for the restriction on the discharge. By putting a more limiting dis-charge on the outlet, the flow rate through the device for a given set of pumping cir-cumstances (viscosity, density, system suction, and discharge head) is reduced and the residence time in the machine for a given particle or droplet is increased. The longer residence time increases the probability that a particle has to travel through the highest shearing zones and, thereby, be reduced to the smallest size that the machine is capable of producing. • • • • " ' ; • " * * «L £ J- •-

1998 ◽  
pp. 358-360
Keyword(s):  
Particle Size ◽  
Residence Time ◽  
Flow Rate ◽  
Shear Zones ◽  
High Shear ◽  
Single Pass ◽  
Fine Dispersion ◽  
Wide Range ◽  
Maximum Particle ◽  
Pass Through

scholarly journals Hydroxyl-radical scavenging activity of hydrogen does not significantly contribute to its biological function

2021 ◽  
Author(s):  
Qinjian Li ◽  
Fei Xie ◽  
Yang Yi ◽  
Pengxiang Zhao ◽  
Xin Zhang ◽  
...  
Keyword(s):  
Hydroxyl Radicals ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Published Data ◽  
Oh Radicals ◽  
Dependent Manner ◽  
Protective Effects ◽  
Beneficial Effects ◽  
Wide Range ◽  
Depth Study

AbstractSince Ohsawa et al. reported a biological antioxidant function of hydrogen in 2007, researchers have now shown it to exert protective effects in a wide range of human and animal disease models. Clinical observations and scientific arguments suggest that a selective scavenging property of H2 cannot adequately explain the beneficial effects of hydrogen. However, there is no experiment challenging the original published data, which suggested that molecular hydrogen dissolved in solution reacts with hydroxyl radicals in cell-free systems. Here we report that a hydrogen-saturated solution (0.6 mM) did not significantly reduce hydroxyl radicals in the Fenton system using 1 mM H2O2. We replicated the same condition as Ohsawa’s study (i.e. 5 μM H2O2), and observed a decrease in •OH radicals in both the H2-rich and N2-rich solutions, which may be caused by a decreased dissolved oxygen concentration. Finally, we determined the effect of hydrogen on a high-valence iron enzyme, horseradish peroxidase (HRP), and found that hydrogen could directly increase HRP activity in a dose-dependent manner. Overall, these results indicate that although H2 and •OH can react, the reaction rate is too low to have physiological function. The target of hydrogen is more complex, and its interaction with enzymes or other macro-molecules deserve more attention and in-depth study.

scholarly journals Simulation of P2X-mediated calcium signaling in microglia

2018 ◽  
Author(s):  
Ben Chun ◽  
Bradley D. Stewart ◽  
Darin Vaughan ◽  
Adam D. Bachstetter ◽  
Peter M. Kekenes-Huskey
Keyword(s):  
Computational Model ◽  
Purinergic Receptor ◽  
Receptor Activation ◽  
Quantitative Model ◽  
Published Data ◽  
Transcriptional Responses ◽  
Extracellular Adenosine ◽  
Wide Range ◽  
Intracellular Ca

AbstractMicroglia function is orchestrated through highly-coupled signaling pathways that depend on calcium (Ca2+). In response to extracellular adenosine triphosphate (ATP), transient increases in intracellular Ca2+ driven through the activation of purinergic receptors, P2X and P2Y, are sufficient to promote cytokine synthesis and potentially their release. While steps comprising the pathways bridging purinergic receptor activation with transcriptional responses have been probed in great detail, a quantitative model for how these steps collectively control cytokine production has not been established. Here we developed a minimal computational model that quantitatively links extracellular stimulation of two prominent ionotropic puriner-gic receptors, P2X4 and P2X7, with the graded production of a gene product, namely the tumor necrosis factor α (TNFα) cytokine. In addition to Ca2+ handling mechanisms common to eukaryotic cells, our model includes microglia-specific processes including ATP-dependent P2X4 and P2X7 activation, activation of NFAT transcription factors, and TNFα production. Parameters for this model were optimized to reproduce published data for these processes, where available. With this model, we determined the propensity for TNFα production in microglia, subject to a wide range of ATP exposure amplitudes, frequencies and durations that the cells could encounter in vivo. Furthermore, we have investigated the extent to which modulation of the signal transduction pathways influence TNFα production. Our key findings are that TNFα production via P2X4 is maximized at low ATP when subject to high frequency ATP stimulation, whereas P2X7 contributes most significantly at millimolar ATPranges. Given that Ca2+ homeostasis in microglia is profoundly important to its function, this computational model provides a quantitative framework to explore hypotheses pertaining to microglial physiology.

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