Lamprophyres from Turiy Cape and Kandalaksha Devonian dykes (Kola peninsula, Russia) : petrography,geochemistry and mineral composition

2020 ◽  
Author(s):  
Alexei Vozniak ◽  
Lyudmila Sazonova ◽  
Anna Nosova
Keyword(s):  
Crustal Contamination ◽  
Medium Size ◽  
Nickel Concentration ◽  
Common Source ◽  
Carbonate Apatite ◽  
Kola Alkaline Province ◽  
Significant Difference ◽  
Compositional Diversity ◽  
Dyke Swarms ◽  
Opaque Minerals

<p>Study of phenocryst and megacryst mineral associations of alkali rocks is the key to understanding an evolution and a source of the rocks.</p><p>In the Devonian Kola alkaline province (KAP) along with large mafic-ultramafic massifs there are several synchronous swarms of lamprophyre dykes. The dyke swarms occur mainly in the Kandalaksha graben. As suggest, their compositional diversity is caused by fractional crystallization and crustal contamination and a primary melt of lamprophyre was generated from a common source.  </p><p>We have studied two dykes of the Turiy Cape swarm and  the Kandalaksha swarm in the vicinity of the Kandalaksha town. The aim of  study was to determine the source of lamprophyre melts based on petrography, geochemistry and detailed investigation of clinopyroxene and olivine.</p><p>Two principal petrographical types: alkali lamprophyres (Cb-Anl monchiquite) and ultramafic lamprophyres (Cpx ailikites and mela-alikites) in the Kandalaksha swarm were observed. Alkali lamprophyres contain medium size (0.3 – 1 cm) phenocrysts of olivine, clinopyroxene, magnetite, phlogopite. A groundmass contains analcime, clinopyroxene, various amounts of carbonate (from 0 to 30-40 %), pyrite, apatite, ilmenite.</p><p>Ultramafic lamprophyres contain medium size (0.5 – 1 cm) phenocrysts of olivine, clinopyroxene, phlogopite and amphibole. A groundmass contains phlogopite, carbonate, apatite, clinopyroxene, garnet, titanite and opaque minerals.</p><p>The most important chemical features of the  alkali lamprophyres are undersaturation of SiO2 (31.04-40.54 wt%), high alkali contents (3.86 – 6.47 wt% K2O+Na2O) and their sodium specification (K2O/Na2O - 0.36-0.68), whereas ultramafic lamprophyres  have lower alkali contents (1.73-3.39 wt% K2O+Na2O), and potassium specification (K2O/Na2O -  1 -2.31). They also contain less SiO2 (27.73 – 34.11 wt%).</p><p>The Turiy Cape dykes are characterized by only a single petrographic type  - alkali lamprophyres (Cb-Anl and Ne-Anl monchiquites). They contain small and medium size (0.1 – 1 cm) phenocrysts of olivine, clinopyroxenes, amphiboles, magnetite, phlogopite. A groundmass contains analcime, nepheline, aegirine, phlogopite, garnet, perovskite, apatite and opaque minerals.</p><p>Rocks of the Turiy Cape dykes are SiO2 undersaturated (33.93 - 41.86 wt%), and contain extremely high alkalis (5.62-14.51 wt% K2O+Na2O) and all of them have sodium specification (0.11-0.68 K2O/Na2O).</p><p>The most primitive core of clinopyroxenes in the Kandalaksha dykes are high magnesian (#Mg – 0.76 – 0.87), low titanian (0,5 – 1,09 wt% TiO2) and contains chromium (0.1-1.1 wt% Cr2O3). The clinopyroxenes of the Tyriy Cape dykes have high magnesian core (#Mg 0.79-0.83, 1.48-2.05 wt% TiO2, 0.12-0.4 wt% Cr2O3).</p><p>Olivines in the Kandalaksha lamprophyres have more primitive composition in comparison with olivines from the Turiy Cape ones. The #Mg of Kandalaksha olivines varies from 0.84 to 0.87, nickel concentration varies from 1500 to 2500 ppm and the  #Mg of Turiy Cape olivines varies from 0.82 to 0.85, nickel concentration varies from 500 to 1000 ppm.  </p><p>Based on composition of primary minerals we suggest that compositional diversity of both dyke swarms were formed due to crystal fractionation processes. Though, the significant difference in chemistry of whole rocks and clinopyroxene and olivine composition do not support a common source for of the  Turiy Cape and Kandalaksha dykes.</p><p>This work was supported by the Russian Science Foundation under Grant No. 19-17-00024.</p><p> </p>

scholarly journals Women’s Economic Empowerment in Vietnam: Performance and Constraints of Female-Led Manufacturing SMEs

2021 ◽  
Vol 14 (6) ◽  
pp. 255
Author(s):  
MinhTam Bui ◽  
Trinh Q. Long
Keyword(s):  
Labor Productivity ◽  
Small And Medium Enterprises ◽  
Manufacturing Sector ◽  
Value Added ◽  
Medium Size ◽  
Formal Sector ◽  
Firm Level ◽  
Average Value ◽  
Significant Difference ◽  
Medium Enterprises

This paper identifies whether there was a performance difference among micro, small and medium enterprises (MSMEs) led by men and by women in Vietnam during the period 2005–2013 and aims to provide explanations for the differences, if any, in various performance indicators. The paper adopts a quantitative approach using a firm-level panel dataset in the manufacturing sector in 10 provinces/cities in Vietnam in five waves from 2005 to 2013. Fixed effect models are estimated to examine the influence of firm variables and demographic, human capital characteristics of owners/managers on firms’ value added, labor productivity and employment creation. We found that men led MSMEs did not outperform those led by women on average. Although the average value added was lower for female-led firms in the informal sector, the opposite was true in the formal sector where women tend to lead medium-size firms with higher value added and labor productivity. The performance disparity was more envisaged across levels of formality and less clear from a gender perspective. Moreover, while firms owned by businessmen seemed to create more jobs, firms owned by women had a higher share of female employees. No significant difference in business constraints faced by women and by men was found.

scholarly journals Increasing the Authenticity of Group Assignments in an Online Research Course may Lead to Higher Academic Achievement

2015 ◽  
Vol 10 (2) ◽  
pp. 158
Author(s):  
Cari Merkley
Keyword(s):  
Student Perceptions ◽  
Teaching Quality ◽  
The United States ◽  
Annotated Bibliography ◽  
Teaching Presence ◽  
Medium Size ◽  
Full Time ◽  
Library Research ◽  
Significant Difference ◽  
Online Library

A Review of: Finch, J. L., & Jefferson, R. N. (2013). Designing authentic learning tasks for online library instruction. Journal of Academic Librarianship, 39(2), 181-188. http://dx.doi.org/10.1016/j.acalib.2012.10.005 Abstract Objective – To explore what impact assigning authentic tasks to students deliberately grouped by their majors in an online library research course has on student perceptions of teaching quality (teaching presence) and satisfaction. Design – Empirical comparative study. Setting – Medium-size (10,500 full-time students) liberal arts college in the United States of America. Subjects – 33 undergraduate students enrolled in a library research course. Methods – The study focusses on two sections of a one-credit online library research course taught by library faculty. The 17 students in the Spring “express” section were randomly assigned to groups and asked to complete a group annotated bibliography project using MLA style (Class Random). The 16 students registered in the Summer section of the same course were grouped by their majors, and asked to complete a modified version of the annotated bibliography group project in which they were asked to identify and then utilize the citation style most appropriate for their discipline (Class Deliberate). Students in Class Deliberate also received instruction around the role of subject specific citation styles in scholarly communication. Both sections completed a final assignment in which they developed a portal of resources to support their future studies or careers. All 33 students in both sections were invited to complete a modified online version of the Community of Inquiry (COI) survey consisting of 16 questions relating to student perceptions of the course’s teaching and cognitive presences. Questions relating to social presence were not administered. The final grades awarded to all students in both sections were also analyzed. Main Results – A total of 59% of the students in Class Random (10/17) and 67% of the students in Class Deliberate (11/16) completed the online survey. There were no statistically significant differences in the survey responses between the two sections with both groups of students rating the instructor’s teaching presence and the course’s cognitive presence highly. Only 40% of the respondents from Class Random and 46% from Class Deliberate agreed that working with peers facilitated their learning. The mean final grade received by students in Class Deliberate was 95.27 versus 86.15 in Class Random, a statistically significant difference (p

The finance of innovation in Africa

2019 ◽  
Vol 23 (3) ◽  
pp. 348-382 ◽  
Author(s):  
Misraku Molla Ayalew ◽  
Zhang Xianzhi ◽  
Demis Hailegebreal Hailu
Keyword(s):  
Developing Countries ◽  
Trade Credit ◽  
Innovation Process ◽  
Medium Size ◽  
African Countries ◽  
Firm Level ◽  
Content Type ◽  
Significant Difference ◽  
Innovative Firms ◽  
Finance Innovation

Purpose The purpose of this paper is to investigate how firms in developing countries finance innovation. Notably, the study seeks to investigate whether innovative firms exhibit financing patterns different from those of non-innovative ones. It also examines the effect of financing sources on firm’s probability to innovate. Design/methodology/approach The study utilizes firm-level data from the World Bank Enterprise Survey. From 28 African countries, 11,173 firms have been included in the sample. A statistical t-test is used for two independent samples and logistic regression models. Findings The results show that innovative firms, specifically innovative small- and medium-size firms exhibit financing patterns different from non-innovative peers. Further analysis indicates that there is no statistically significant difference between the financing patterns of innovative and non-innovative large firms. In Africa, innovation is mostly financed using internal sources and bank finance. Equity finance and bank finance have shown a higher effect followed by internal finance, finance from non-bank financial institutions and trade credit finance on firms’ probability to innovate. Practical implications The management of innovative firms should reduce dependency on short-term and retained earning financing and increase the use of long-term instruments improve innovation performance. Social implications A pending policy task for African leaders is to design and evaluate reforms to create a strong financial sector that willing to support the innovation process. Originality/value This study contributes to the existent literature on finance of innovation by examining how firms finance innovation activities in developing countries. This study provides evidence on how innovative firms exhibit financing patterns different from non-innovative ones from developing countries.

Vibration Transmissibility on Foot during Controlling and Operating Car Accelerator Pedal

2013 ◽  
Vol 471 ◽  
pp. 151-155
Author(s):  
A.R. Yusoff ◽  
Baba M. Deros ◽  
D.D.I Daruis
Keyword(s):  
Lower Extremity ◽  
Medium Size ◽  
Accelerator Pedal ◽  
Vehicle Engine ◽  
Large Size ◽  
Honestly Significant Difference ◽  
Significant Difference ◽  
Vibration Transmissibility ◽  
Post Hoc ◽  
The Relationship

The purpose of this paper is to discuss the vibration transmissibility from a cars body to pedal-pad, and the lower extremity, especially on the foot. The vibration transmissibility will occur when the foot interacts with the pedal-pad once the vehicle engine is turned on. The vibrations transmissibility will cause drivers discomfort, especially on the lower extremity due to fatigue and tiredness of the foot. The relationship between vibration transmissibility with the different sizes pedal-pad to the foot, and whether it can contribute to the foot discomfort during handling and controlling pedal-pad while driving is investigated. The variables are the different sizes of pedal-pad. Data was recorded from foot on three different sizes of pedal-pads. The data was measured in root mean square (r.m.s) unit, of the frequency weighted acceleration (m/s2) for every minute. The result for the foot-transmitted-vibration shows the ratio value of medium sized pedal-pad is greater than 1; compared to small sized and large sized pedal-pads which is less than 1. Analysis of One-way Anova shows that the mean of different sizes of pedal-pad is significant. Tukeyspost-hocwith HSD (Honestly Significant Difference) test on the foot transmitted-vibration proves that the means for medium size pedal-pad is the highest compared with the small and large size pedal-pads.

Geochemistry and uranium-lead isotopic ages of volcanic rocks associated with Ladakh batholith, western Himalaya: Implications for petrogenesis and tectonic evolution

2020 ◽  
Author(s):  
Nongmaithem Lakhan Singh ◽  
Athokpam Krishnakanta Singh
Keyword(s):  
Oceanic Crust ◽  
Volcanic Rocks ◽  
Crustal Contamination ◽  
Primary Source ◽  
Western Himalaya ◽  
Mature Stage ◽  
Northern Margin ◽  
Felsic Volcanic ◽  
Compositional Diversity ◽  
Felsic Volcanic Rocks

<p>We present zircon U-Pb ages and whole-rock geochemistry along with mineral chemistry of the Khardung volcanic rocks outcropped in the northern margin of the Ladakh batholith in order to constrain their origin and tectono-magmatic history. These volcanic rocks are sandwiched between the Ladakh batholith in the south and the Shyok suture zone in the north and span a continuous compositional range from basalt to rhyolite, although mafic rocks are minor and intermediate to felsic rocks are volumetrically predominant. New zircon U-Pb dating for andesite coupled with two rhyolitic rocks yield 69.71 Ma, 62.49 Ma, and 66.55 Ma, defining the probable span of their magmatism from Late Cretaceous to Palaeogene. Based on their mineralogical and geochemical compositional diversity, the Khardung volcanic rocks are categorized as intermediate volcanic rocks (basaltic andesite-andesite) and felsic volcanic rocks (dacite-rhyolite). The intermediate volcanic rocks are marked by low SiO<sub>2</sub> (52.80-61.31 wt.%), enriched LREEs, and negative HFSEs (Nb, Ti, Zr) anomalies whereas,  felsic volcanic rocks are characterized by high SiO<sub>2</sub> (64.52-79.19 wt.%), pronounced negative Eu anomalies, enriched LREE and concave-downward HREE’s and negative HFSE’s (Nb, Ti) anomalies. Both the intermediate and felsic volcanic rocks exhibit quartz, sanidine, albite, bytownite, and diopside as their dominant mineral phases. Geochemical signatures indicate that the fractional crystallization and crustal contamination played a significant role in the evolution of the Khardung volcanic rocks and their geochemical diversity probably resulted from the partial melting of the common primary source, which had been metasomatized by variable contributions of fluids released from down going Neo-Tethyan oceanic crust. Thus, the Khardung volcanic rocks could be considered as a product of mature stage of arc magmatism during the subduction of the Neo-Tethyan oceanic crust, which occurred during Early Cretaceous to Palaeogene, prior to the main collision between the Indian and Asian plates.</p>

scholarly journals Antiatherosclerotic Potential of Clopidogrel: Antioxidant and Anti-Inflammatory Approaches

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Najah R. Hadi ◽  
Bassim I. Mohammad ◽  
Ihsan M. Ajeena ◽  
Hussam H. Sahib
Keyword(s):  
Lipid Profile ◽  
Atherosclerotic Lesion ◽  
Immunohistochemical Analysis ◽  
Atherogenic Diet ◽  
Atherogenic Index ◽  
Vehicle Group ◽  
Medium Size ◽  
Control Group ◽  
Serum Triglycerides ◽  
Significant Difference

Background. Atherosclerosis is characterized by endothelial dysfunction, vascular inflammation, and the buildup of lipids, cholesterol, calcium, and cellular debris within the intima of the walls of large and medium size arteries.Objective. To evaluate the effect of clopidogrel on atherosclerosis progression.Materials and Methods. A total of 28 local domestic rabbits were assigned to four groups: normal control, atherogenic control, vehicle control, and clopidogrel treated. Serum triglycerides, total cholesterol, HDL-C, plasma high sensitive C-reactive protein (hsCRP), plasma malondialdehyde (MDA), and plasma reduced glutathione (GSH) were measured at the end of the experiment. Immunohistochemical of aortic atherosclerotic changes were also performed.Results. There was no statistically significant difference between atherogenic control group and vehicle group. Levels of lipid profile, atherogenic index, hsCRP, and MDA are increased while GSH levels were decreased in animals on atherogenic diet. Immunohistochemical analysis showed that aortic expressions of VCAM-1, MCP-1, TNF-α, and IL-17A were significantly increased in atherogenic control group. Histopathologic finding showed that animals on atherogenic diet have significant atherosclerotic lesion. Compared to atherogenic control group clopidogrel do not have significant effect on lipid profile. Clopidogrel significantly reduces hsCRP and MDA levels and increases GSH level. Furthermore, clopidogrel treatment significantly reduced aortic expressions parameters and the histopathologic examination of the aortic arch showed a significant reduction of atherosclerotic lesion.Conclusions. This study outlines how clopidogrel reduces lipid peroxidation, systemic inflammation, and aortic expression of inflammatory markers and hence reduces the progression of atherosclerosis.

scholarly journals Antioxidants and the Battle for the Brain: Antioxidant Effectiveness Against a Beta-amyloid Challenge

2021 ◽  
Vol 5 (Supplement_2) ◽  
pp. 916-916
Author(s):  
Kelly Parker ◽  
Annika Rotvold ◽  
Yeong Rhee
Keyword(s):  
Pc12 Cells ◽  
Beta Amyloid ◽  
Common Source ◽  
Protective Effects ◽  
Antioxidant Treatment ◽  
Funding Sources ◽  
Antioxidant Effectiveness ◽  
Significant Difference ◽  
Student’S T ◽  
The Brain

Abstract Objectives The objective of this study was to determine the protective effects of antioxidants against oxidative damage in PC12 cells when treated with beta-amyloid (BA), a common source of reactive oxygen species (ROS) in older adult brains. Methods PC12 cells (2 × 105 cells/mL) were treated with secoisolariciresinol diglucoside (SDG, 50 or 100 μM) or control antioxidants, superoxide dismutase (SOD, 100 U/mL) or catalase (100 U/mL), for 2 hours, then treated with 10 μM BA for 24 hours. After antioxidant and BA treatments, ROS and lactate dehydrogenase (LDH) were measured using assay kits. Differences in ROS and LDH between control (no antioxidant and BA treatments) and experimental groups were analyzed by Student's t-tests. Results Cells treated with BA without an antioxidant treatment showed a significant reduction in LDH (p < 0.01) when compared to the control, but did not differ in ROS. Cells treated with BA and catalase showed no significant difference in LDH. LDH and ROS were significantly reduced in BA and SOD treated cells (p < 0.01 and < 0.05, respectively) compared to the control. However, LDH or ROS in both SOD and catalase treated cells, either with or without BA treatment, was not different compared to the control. BA and SDG (50 μM or 100 μM) treated cells showed significant reductions in ROS, but no significant difference in LDH compared to the control. Conclusions An antioxidant, SDG, found in flaxseed shows promise for reducing oxidative stress in cells. Funding Sources The authors gratefully acknowledge funding provided by North Dakota State University's College of Human Sciences and Education.

scholarly journals Knowledge and attitude towards corneal donation

2021 ◽  
Author(s):  
Khalid Mohammed Aloudah ◽  
Abdulaziz Ahmed Ataweel ◽  
Sajida Agha ◽  
Syed Waqas Hussain Shah
Keyword(s):  
Medical Students ◽  
Cross Sectional Study ◽  
Common Source ◽  
Cross Sectional ◽  
Raising Awareness ◽  
Significant Difference ◽  
Level Of Knowledge ◽  
Corneal Donation ◽  
Knowledge And Attitude ◽  
Study Participants

Objective: Raising awareness on corneal donation among doctors and medical students is an important step to attain more local corneal donations. The objective of the study was to evaluate the knowledge and attitude of medical students regarding corneal donations. Method: A cross-sectional study was conducted among 5th and final year’s medical students from August 2019 to October 2019. Non-probability convenience sampling was employed. A self-administered questionnaire that evaluated the aspects of knowledge and attitudes about corneal donation was used after informed consent was taken. SPSS 20 was used for statistical analysis. Results: The study participants had a mean score of 3.24+1.86 on the knowledge aspect. Eighty percent correctly recognized that people who die with AIDS cannot donate. The most chosen reason for eyes donation was that pledged corneas can give vision to a blind person (n=66, 47%). Religious beliefs were a major obstacle for eye donation (n=62, 44%). The internet was identified by 79 (56%) of the participants to be the most common source of information. No significant difference was found in the knowledge level of the 5th year (3.31 + 1.84) and final year (3.17 + 1.89) medical students (p=0.65). Conclusion: The study showed a low level of knowledge of students about corneal donations. While raising awareness among medical students is important to increase donation rates, media and internet are not enough for improving the student’s knowledge. Information about the basics of corneal donation is important to fill gaps in knowledge. Keywords: Knowledge, attitude, corneal donation, Medical students

scholarly journals Spatial and Temporal Variation of Fish Assemblages in Seti Gandaki River, Tanahu, Nepal

2020 ◽  
Vol 10 (2) ◽  
pp. 93-104
Author(s):  
ARCHANA PRASAD ◽  
ANJANA SHRESTHA ◽  
JASH HANG LIMBU ◽  
DEEP SWAR
Keyword(s):  
Community Structure ◽  
Fish Community ◽  
Fish Assemblages ◽  
Mesh Size ◽  
Spatial And Temporal Variation ◽  
Total Hardness ◽  
Medium Size ◽  
Fish Community Structure ◽  
Space And Time ◽  
Significant Difference

The space and time variations of the fish community structure in hill streams of Nepal are poorly understood. This research aims at studying the space and time variation of fish community structure in the Seti Gandaki River, Tanahu, Nepal. The field survey was conducted from July 2017 to June 2018 and the fishes were sampled from six sites using a medium size cast net of mesh size ranging from 3 mm to 6 mm mesh size, 25-33 feet length and 3.5-5 feet width, with the help of local fisher man. A total of 1,440 individuals were caught representing 46 species belonging to three order, nine families and 23 genera. The analysis of similarity (ANOSIM) showed significant difference in space (R = 0.824, P = 0.001) but not in time (R = 0.135, P = 0.021). On the basis of similarity percentage (SIMPER) analysis, 85.43% similarity was found among the seasons and major contributing species were Barilius bendelisis (8.44%) followed by B. vagra (7.79%), Tor putitora (7.27%), Garra gotyla (7%), Acanthocobotis botia (6.7%), Neolissochilus hexagonolepis (6.64%), Barilius shacra (6%), B. barila (4.5%) and Opsarius barna (4.37%). On the other hand, 85.24% similarity was found among the sites and major contributing species were B. bendelisis (8.8%) followed by B. vagra (7.6%), G. gotyla (7.27%), T. putitora (7.17%), A. botia (6.97%), N. hexagonolepis (6.7%), B. shacra (6.34%), B. barila (4.7%) and O. barna (4.39%). Results from the Canonical Correspondence Analysis indicated that the environmental variables, such as pH, total hardness, alkalinity, dissolved oxygen and water temperature have shown to determine the fish community structure of Seti Gandaki River. Keywords: Fish diversity, freshwater, habitat, spatio-temporal, stream

Calcium Phosphate Mineralized GBR Membranes: Preparation and Properties

2007 ◽  
Vol 361-363 ◽  
pp. 435-438
Author(s):  
A.H.K. Chou ◽  
Racquel Z. LeGeros ◽  
Dindo Q. Mijares ◽  
C. Frondoza ◽  
John P. LeGeros
Keyword(s):  
Calcium Phosphate ◽  
Cell Response ◽  
Bone Cells ◽  
Phenotypic Expression ◽  
Carbonate Apatite ◽  
Bovine Collagen ◽  
Significant Difference ◽  
Osteoconductive Property ◽  
Ft Ir ◽  
Time Required

The osteoconductive property of calcium phosphate (CaP) biomaterials allow attachment, proliferation, migration, and phenotypic expression of bone cells leading to formation of new bone. The purpose of research is to develop new method of mineralizing commercial GBR membranes with calcium phosphate (CaP) and determine cell response. Resolut Adapt LT (Gore-tex) composed of co-polymer PGA/TMC and Biomend Extend (Zimmer) composed of bovine collagen were used. Membranes were mineralized with CaP using precipitation and new microwave methods. The mineralized and non-mineralized membranes were characterized using SEM, EDS, XRD, FT-IR, and TGA. Cell response to mineralized and non-mineralized membranes was determined using human osteoblastlike cells (MG-63). Microwave method was more efficient in terms of amount of minerals incorporated with membranes and time required. SEM, EDS, and FT-IR identified carbonate apatite in the mineralized membranes. No significant difference in cell proliferation was observed between mineralized and non-mineralized membranes. Greater production of type 1 collagen was observed with CaP mineralized membranes.

Sign in / Sign up

Export Citation Format

Share Document