scholarly journals Formation Conditions and 40Ar/39Ar Age of the Gem-Bearing Boqueirão Granitic Pegmatite, Parelhas, Rio Grande do Norte, Brazil

Minerals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 233 ◽  
Author(s):  
Strmić Palinkaš ◽  
Palinkaš ◽  
Neubauer ◽  
Scholz ◽  
Šoštarić ◽  
...  
Keyword(s):  
Fluid Inclusion ◽  
Melt Inclusions ◽  
Fluid Phase ◽  
Granitic Pegmatite ◽  
Northeast Brazil ◽  
High Quality ◽  
Late Cambrian ◽  
Formation Conditions ◽  
Zone Ii ◽  
Insight Into

The Boqueirão granitic pegmatite, alias Alto da Cabeça pegmatite, is situated in Borborema Pegmatitic Province (BPP) in Northeast Brazil. This pegmatitic province hosts globally important reserves of tantalum and beryllium, as well as significant quantities of gemstones, including aquamarine, morganite, and the high-quality turquoise-blue “Paraíba Elbaite”. The studied lithium-cesium-tantalum Boqueirão granitic pegmatite intruded meta-conglomerates of the Equador Formation during the late Cambrian (502.1 ± 5.8 Ma; 40Ar/39Ar plateau age of muscovite). The pegmatite exhibits a typical zonal mineral pattern with four defined zones (Zone I: muscovite, tourmaline, albite, and quartz; Zone II: K-feldspar (microcline), quartz, and albite; Zone III: perthite crystals (blocky feldspar zone); Zone IV: massive quartz). Huge individual beryl, spodumene, tantalite, and cassiterite crystals are common as well. Microscopic examinations revealed that melt inclusions were entrapped simultaneously with fluid inclusions, suggesting the magmatic–hydrothermal transition. The magmatic–hydrothermal transition affected the evolution of the pegmatite, segregating volatile compounds (H2O, CO2, N2) and elements that preferentially partition into a fluid phase from the viscous silicate melt. Fluid inclusion studies on microcline and associated quartz combined with microthermometry and Raman spectroscopy gave an insight into the P-T-X characteristics of entrapped fluids. The presence of spodumene without other LiAl(SiO3)2 polymorphs and constructed fluid inclusion isochores limited the magmatic–hydrothermal transition at the gem-bearing Boqueirão granitic pegmatite to the temperature range between 300 and 415 °C at a pressure from 1.8 to 3 kbar.

Fluid inclusion microthermometry in Be–Ta–(Li–Sn)-bearing pegmatites from the Borborema Province, Northeast Brazil

2001 ◽  
Vol 173 (1-3) ◽  
pp. 107-123 ◽  
Author(s):  
Hartmut Beurlen ◽  
Marcelo R.R. da Silva ◽  
Claudio de Castro
Keyword(s):  
Fluid Inclusion ◽  
Northeast Brazil ◽  
Borborema Province

scholarly journals The Gossypium stocksii genome as a novel resource for cotton improvement

2021 ◽  
Author(s):  
Corrinne E Grover ◽  
Daojun Yuan ◽  
Mark A Arick ◽  
Emma R Miller ◽  
Guanjing Hu ◽  
...  
Keyword(s):  
Genome Sequence ◽  
De Novo ◽  
Pest Resistance ◽  
Cotton Leaf ◽  
High Quality ◽  
Cotton Leaf Curl Virus ◽  
Cotton Species ◽  
Wild Cotton ◽  
Leaf Curl Virus ◽  
Insight Into

Abstract Cotton is an important textile crop whose gains in production over the last century have been challenged by various diseases. Because many modern cultivars are susceptible to several pests and pathogens, breeding efforts have included attempts to introgress wild, naturally resistant germplasm into elite lines. Gossypium stocksii is a wild cotton species native to Africa, which is part of a clade of vastly understudied species. Most of what is known about this species comes from pest resistance surveys and/or breeding efforts, which suggests that G. stocksii could be a valuable reservoir of natural pest resistance. Here we present a high-quality de novo genome sequence for G. stocksii. We compare the G. stocksii genome with resequencing data from a closely related, understudied species (G. somalense) to generate insight into the relatedness of these cotton species. Finally, we discuss the utility of the G. stocksii genome for understanding pest resistance in cotton, particularly resistance to cotton leaf curl virus.

A myriad of melt inclusions: a synchrotron microtomography study of melt inclusions and vapour bubbles from Colli Albani (Italy)

2021 ◽  
Author(s):  
Corin Jorgenson ◽  
Luca Caricchi ◽  
Michael Stueckelberger ◽  
Giovanni Fevola ◽  
Gregor Weber
Keyword(s):  
Melt Inclusions ◽  
Melt Inclusion ◽  
Fluid Phase ◽  
Volcanic Eruptions ◽  
Mineral Chemistry ◽  
Magma Ascent ◽  
Vapour Bubble ◽  
Electron Synchrotron ◽  
Colli Albani ◽  
Synchrotron Microtomography

<p>Melt inclusions provide a window into the inner workings of magmatic systems. Both mineral chemistry and volatile distributions within melt inclusions can provide valuable information about the processes modulating magma ascent and preceding volcanic eruptions. Many melt inclusions host vapour bubbles which can be rich in CO<sub>2</sub> and H<sub>2</sub>O and must be taken into consideration when assessing the volatile budget of magmatic reservoirs. These vapour bubbles can be the product of differential volumetric contraction between the melt inclusion and host phase during an eruption or indicate an excess fluid phase in the magma reservoir. Thus, determining the distribution of volatiles between melt and vapour bubbles is integral to our fundamental understanding of melt inclusions, and by extension the evolution of volatiles within magmatic systems.</p><p>A large dataset of 79 high-resolution tomographic scans of clinopyroxene and leucite phenocrysts from the Colli Albani Caldera Complex (Italy) was recently acquired at the German Electron Synchrotron (DESY). These tomograms allow us to quantify the volume of melt inclusions and associated vapour bubble both glassy and microcrystalline melt inclusions. Notably, in the glassy melt inclusions the vapour bubbles exist either as a single large vapour bubble in the middle of the melt inclusion or as several smaller vapour bubbles distributed around the edge of the melt inclusion. These two types of melt inclusions can coexist within a single crystal. We suggest that the occurrence of these rim- bubbles is caused by one of two exsolution pathways, either pre-entrapment and bubble migration or post entrapment with preferential exsolution at the rims. By combining the analysis of hundreds of melt inclusions with the chemistry of the host phase we aim to unveil magma ascent rates and distribution of excess fluids within the magmatic system of Colli Albani, which produced several mafic-alkaline large volume ignimbrites.</p>

The global elements of vital signs' assessment: a guide for clinical practice

2021 ◽  
Vol 30 (16) ◽  
pp. 956-962
Author(s):  
Malcolm Elliott
Keyword(s):  
Clinical Practice ◽  
Outcomes Research ◽  
Quality Care ◽  
Vital Signs ◽  
Clinical Judgement ◽  
Evidence Based ◽  
Valuable Insight ◽  
High Quality ◽  
Culture Tradition ◽  
Insight Into

The assessment of vital signs is critical for safe, high-quality care. Vital signs' data provide valuable insight into the patient's condition, including how they are responding to medical treatment and, importantly, whether the patient is deteriorating. Although abnormal vital signs have been associated with poor clinical outcomes, research has consistently found that vital signs' assessment is often neglected in clinical practice. Factors contributing to this include nurses' knowledge, clinical judgement, culture, tradition and workloads. To emphasise the importance of vital signs' assessment, global elements of vital signs' assessment are proposed. The elements reflect key principles underpinning vital signs' assessment and are informed by evidence-based literature.

scholarly journals Application of the Transhipment Model to Development of the Seed Industry in Northeast Brazil

1976 ◽  
Vol 8 (2) ◽  
pp. 109-113
Author(s):  
Fred H. Tyner ◽  
Roberto G. Campos
Keyword(s):  
United States ◽  
Technical Assistance ◽  
Developing Economies ◽  
Total Yield ◽  
The United States ◽  
Northeast Brazil ◽  
Good Seed ◽  
High Quality ◽  
Credit Availability ◽  
Seed Industry

The importance of agriculture in developing economies is reflected in the share of the Gross Domestic Product (GDP) originating in that sector and in the percent of population working in that sector. Brazil received 19 percent of its GDP from agriculture in 1968, and 60 percent of its population was in agriculture. In contrast, only three percent of GDP came from agriculture in the United States, and only six percent of the population was employed in agriculture.Development of a country's agriculture is dependent on a multitude of factors—not the least of which is availability and use of good seed. Use of high quality seeds increases total yield; allows for more efficient use of fertilizers, pesticides and irrigation because of greater uniformity, better stands and more vigorous plants; usually results in higher quality produce; requires lower planting rates; and usually reduces weed, disease and soil insect problems. Other inputs such as fertilizers, pesticides, technical assistance and credit availability are necessary to achieving a sound agriculture.

scholarly journals Unveiling the nature of the brightest z > 6 galaxies with ALMA and JWST

2019 ◽  
Vol 15 (S352) ◽  
pp. 20-20
Author(s):  
Rebecca Bowler
Keyword(s):  
Star Formation ◽  
Rest Frame ◽  
Small Samples ◽  
Star Forming ◽  
Lyman Alpha ◽  
Alpha Emission ◽  
Formation Conditions ◽  
Formation And Evolution ◽  
Insight Into

AbstractThe very brightest z > 6 galaxies are ideal laboratories for studying the physical properties of star-forming objects into the epoch of reionization. Selected from degree-scale, ground-based fields, these rare objects provide a key insight into early dust production and may harbour faint AGN. Targeted follow-up of small samples have unexpectedly shown both Lyman-alpha emission and other rest-frame UV lines (e.g CIV and HeII), suggesting unique star-formation conditions (or AGN) at early times. Furthermore, ALMA observations have revealed that 75% of the star-formation in these galaxies may be obscured. I will talk about HST/ALMA follow-up of bright z ∼ 7 LBGs in COSMOS and present new results from even brighter samples from z = 6 – 9 selected over ∼ 5 deg2. The power of both ALMA and JWST, coupled with the intrinsic luminosity of these sources, will provide a unique insight into the formation and evolution of vigorously star-forming galaxies in the first billion years.

Comparison of fluid processes in coexisting wolframite and quartz from a giant vein-type tungsten deposit, South China: Insights from detailed petrography and LA-ICP-MS analysis of fluid inclusions

2019 ◽  
Vol 104 (8) ◽  
pp. 1092-1116 ◽  
Author(s):  
Jun-Yi Pan ◽  
Pei Ni ◽  
Ru-Cheng Wang
Keyword(s):  
Fluid Inclusion ◽  
Fluid Inclusions ◽  
South China ◽  
Inductively Coupled Plasma ◽  
Fluid Phase ◽  
Fluid Temperature ◽  
Depositional Sequence ◽  
Ms Analysis ◽  
Icp Ms ◽  
Tungsten Mineralization

Abstract Granite-related wolframite-quartz veins are the world's most important tungsten mineralization and production resource. Recent progress in revealing their hydrothermal processes has been greatly facilitated by the use of infrared microscopy and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) analysis of both quartz- and wolframite-hosted fluid inclusions. However, owing to the paucity of detailed petrography, previous fluid inclusion studies on coexisting wolframite and quartz are associated with a certain degree of ambiguity. To better understand the fluid processes forming these two minerals, free-grown crystals of intergrown wolframite and quartz from the giant Yaogangxian W deposit in South China were studied using integrated in situ analytical methods including cathodoluminescence (CL) imaging, infrared microthermometry, Raman microspectroscopy, and fluid inclusion LA-ICP-MS analysis. Detailed crystal-scale petrography with critical help from CL imaging shows repetition of quartz, wolframite, and muscovite in the depositional sequence, which comprises a paragenesis far more complex than previous comparable studies. The reconstruction of fluid history in coexisting wolframite and quartz recognizes at least four successive fluid inclusion generations, two of which were entrapped concurrently with wolframite deposition. Fluctuations of fluid temperature and salinity during precipitation of coexisting wolframite and quartz are reflected by our microthermometry results, according to which wolframite-hosted fluid inclusions do not display higher homogenization temperature or salinity than those in quartz. However, LA-ICP-MS analysis shows that both primary fluid inclusions in wolframite and quartz-hosted fluid inclusions associated intimately with wolframite deposition are characterized by strong enrichment in Sr and depletion in B and As compared to quartz-hosted fluid inclusions that are not associated with wolframite deposition. The chemical similarity between the two fluid inclusion generations associated with wolframite deposition implies episodic tungsten mineralization derived from fluids exhibiting distinct chemical signatures. Multiple chemical criteria including incompatible elements and Br/Cl ratios of fluid inclusions in both minerals suggest a magmatic-sourced fluid with the possible addition of sedimentary and meteoric water. Combined with microthermometry and Raman results, fluid chemical evolution in terms of B, As, S, Sr, W, Mn, Fe, and carbonic volatiles collectively imply fluid phase separation and mixing with sedimentary fluid may have played important roles in wolframite deposition, whereas fluid cooling and addition of Fe and Mn do not appear to be the major driving factor. This study also shows that fluid inclusions in both wolframite and coexisting quartz may contain a substantial amount of carbonic volatiles (CO2 ± CH4) and H3BO3. Ignoring the occurrence of these components can result in significant overestimation of apparent salinity and miscalculation of LA-ICP-MS elemental concentrations. We suggest that these effects should be considered critically to avoid misinterpretation of fluid inclusion data, especially for granite-related tungsten-tin deposits.

Insight into the Al/N-GaN barrier property to realize high quality n-type Ohmic contact

2020 ◽  
Vol 818 ◽  
pp. 152855 ◽  
Author(s):  
Ting Wang ◽  
Zhihua Xiong ◽  
Juanli Zhao ◽  
Ning Wu ◽  
Kun Du ◽  
...  
Keyword(s):  
Ohmic Contact ◽  
Barrier Property ◽  
High Quality ◽  
Insight Into
Sign in / Sign up

Export Citation Format

Share Document