scholarly journals Evaporite weathering and deposition as a long-term climate forcing mechanism

Geology ◽  
2020 ◽  
Author(s):  
Graham A. Shields ◽  
Benjamin J.W. Mills
Keyword(s):  
Calcium Sulfate ◽  
Climate Forcing ◽  
Silicate Weathering ◽  
Carbonate Precipitation ◽  
Sulfate Deposition ◽  
Mutual Dependence ◽  
Carbonate Sedimentation ◽  
Global Cooling ◽  
First Time

Although it is widely accepted that Earth’s long-term surface temperature is regulated by the mutual dependence of silicate weathering and climate on CO2, the root causes of some climatic events remain unresolved. We show here for the first time that imbalances between evaporite weathering and deposition can affect climate through the process of carbonate sedimentation. Calcium sulfate weathering supplies Ca2+ ions to the ocean unaccompanied by carbonate alkalinity, so that increased carbonate precipitation strengthens greenhouse forcing through transfer of CO2 to the atmosphere. Conversely, calcium sulfate deposition weakens greenhouse forcing, while the high depositional rates of evaporite giants may overwhelm the silicate weathering feedback, causing several degrees of planetary cooling. Non-steady-state evaporite dynamics and related feedbacks have hitherto been overlooked as drivers of long-term carbon cycle change. Here, we illustrate the importance of evaporite deposition, in particular, by showing how a series of massive depositional events contributed to global cooling during the mid–late Miocene.

Evaporite dynamics and their effects on global climate and oxygen

2021 ◽  
Author(s):  
Graham Shields ◽  
Benjamin Mills
Keyword(s):  
Time Scales ◽  
Calcium Ions ◽  
Calcium Sulfate ◽  
Global Climate ◽  
Sulfur Cycle ◽  
Silicate Weathering ◽  
Carbonate Precipitation ◽  
Sulfate Deposition ◽  
Biogeochemical Models

<p>Evaporite weathering and deposition are seldom in balance even on million-year time-scales with grand depositional events superimposed against a background of more slowly varying weathering. Despite such imbalance, biogeochemical models generally assume that evaporite weathering and deposition rates are equal on all time scales. Changes in evaporite dynamics through time will likely impact oxidant budgets through the sulfur cycle and we have shown this to have been especially significant during Proterozoic times. Recently, we proposed that imbalances between evaporite weathering and deposition can also affect climate through the process of carbonate sedimentation. Calcium sulfate weathering supplies calcium ions to the ocean unaccompanied by carbonate alkalinity, so that increased carbonate precipitation strengthens greenhouse forcing through transfer of carbon dioxide to the atmosphere. Conversely, calcium sulfate deposition weakens greenhouse forcing, while the high depositional rates of evaporite giants may overwhelm the silicate weathering feedback, causing several degrees of planetary cooling. Non-steady-state evaporite dynamics and related feedbacks have hitherto been overlooked as drivers of long-term carbon cycle change. In this talk, we illustrate the importance of evaporite deposition, in particular, by showing how a series of massive depositional events contributed to global cooling during the mid–late Miocene. Further studies are required to quantify gypsum deposition over time and its possible effects on deoxygenation of the surface environment, especially at times of mass extinction, as well as on climate.</p>

Somatic Embryogenesis and In vitro Plant Regeneration in Vigna trilobata (L.) Verd. - A Potential Pasture Legume

1970 ◽  
Vol 19 (1) ◽  
pp. 89-99
Author(s):  
K. Choudhary ◽  
M. Singh ◽  
M. S. Rathore ◽  
N. S. Shekhawat
Keyword(s):  
Somatic Embryogenesis ◽  
Growth Regulators ◽  
Somatic Embryos ◽  
Basal Medium ◽  
Long Term Study ◽  
Continuous Application ◽  
First Time ◽  
Pasture Legume

This long term study demonstrates for the first time that it is possible to propagate embryogenic Vigna trilobata and to subsequently initiate the differentiation of embryos into complete plantlets. Initiation of callus was possible on 2,4-D. Somatic embryos differentiated on modified MS basal nutrient medium with 1.0 mg/l  of 2,4-D and 0.5 mg/l  of Kn. Sustained cell division resulted in globular and heart shape stages of somatic embryos. Transfer of embryos on to a fresh modified MS basal medium with 0.5 mg/l of Kn and 0.5 mg/l of GA3 helped them to attain maturation and germination. However, the propagation of cells, as well as the differentiation of embryos, were inhibited by a continuous application of these growth regulators. For this reason, a long period on medium lacking these growth regulators was necessary before the differentiation of embryos occurred again. The consequences for improving the propagation of embryogenic cultures in Vigna species are discussed. Key words: Pasture  legume, Vigna trilobata, Globular, Heart shape, somatic embryogenesis D.O.I. 10.3329/ptcb.v19i1.4990 Plant Tissue Cult. & Biotech. 19(1): 89-99, 2009 (June)

An Evaluation of Provincial Macroeconomic Performance in Vietnam

2017 ◽  
pp. 34-47
Author(s):  
Hoi Le Quoc ◽  
Nam Pham Xuan ◽  
Tuan Nguyen Anh
Keyword(s):  
Development Strategy ◽  
Institutional Transformation ◽  
Economic Indicators ◽  
Macroeconomic Performance ◽  
Economic Development Strategy ◽  
Socio Economic Development ◽  
The Cost ◽  
Development Objectives ◽  
First Time

The study was targeted at developing a methodology for constructing a macroeconomic performance index at a provincial level for the first time in Vietnam based on 4 groups of measurements: (i) Economic indicators; (ii) oriented economic indicators; (iii) socio-economic indicators; and (iv) economic - social – institutional indicators. Applying the methodology to the 2011 - 2015 empirical data of all provinces in Vietnam, the research shows that the socio-economic development strategy implemented by those provinces did not provide balanced outcomes between growth and social objectives, sustainability and inclusiveness. Many provinces focused on economic growth at the cost of structural change, equality and institutional transformation. In contrast, many provinces were successful in improving equality but not growth. Those facts threaten the long-term development objectives of the provinces.

NEW VARIETIES OF CURRANTS AND GOOSEBERRY BREEDING PLANTS

1970 ◽  
pp. 41-46
Author(s):  
O. D. Golyaeva ◽  
O. V. Kurashev ◽  
S. D. Knyazev ◽  
А. Yu. Bakhotskaya
Keyword(s):  
Powdery Mildew ◽  
Genetic Basis ◽  
Black Currant ◽  
Leaf Spots ◽  
Agricultural Sciences ◽  
Berry Crops ◽  
New Varieties ◽  
First Time ◽  
Red Currant

The main goal of the scientific institution was and remains to improve the assortment of fruit and berry crops for the development of domestic horticulture. Black currant breeding at VNIISPK was started by A.F Tamarova and continued by the doctor of agricultural Sciences T.P.Ogoltsova and doctor of agricultural Sciences S.D. Knyazev. A long-term breeding program has been developed. The main goals of the program are to create black currant cultivars with continuous resistance to diseases, first of all powdery mildew, as wells resistance to pests, i.e. bud mite. As a result of the long-term work, over 40 black currant cultivars have been developed, 14 of them are zoned. Red currant breeding was led by the candidate of agricultural Sciences L.V. Bayanova; since 2001 the work has been continued by the candidate of agricultural Sciences O.D. Golyaeva. ‘Heinemanns Rote Spӓtlese’, the descendant of R. multiflorum Kit., was involved in the red currant breeding for the first time in Russia. On its genetic basis, a series of late maturing cultivars with long and dense racemes was created. At the Institute, in total 21cultivars of red currants have been developed, 13 of them are zoned. At present, red currant cultivars make up 25.5% of the zoned assortment in Russia. The first research on gooseberries was stated by V.P. Semakin and A.F Tamarova; since 1992 the systematic gooseberry breeding has been carried out by the candidate of agricultural Sciences O.V. Kurashev. On the basis of Grossularia robusta, we have created gooseberry forms that are resistant to powdery mildew and leaf spots. These forms are highly productive, weakly thorned, having bush habit suitable for mechanized harvest. The result of breeding activities was the transfer of 6 gooseberry cultivars to State agricultural testing: ‘Solnechny Zaychik’, ‘Nekrasovsky’, ‘Yupiter’, ‘Zemlianichny’, ‘Moryachok’ and ‘Discovery’.

scholarly journals 1005 Antibiotic-Impregnated Calcium Sulfate Beads Are Not Effective in the Primary Prevention of Infection in Open Femur and Tibia Fractures

2021 ◽  
Vol 108 (Supplement_2) ◽  
Author(s):  
A Fung ◽  
A Ward ◽  
K Patel ◽  
M Krkovic
Keyword(s):  
Primary Prevention ◽  
Infection Rate ◽  
Calcium Sulfate ◽  
Acute Infection ◽  
Open Fractures ◽  
Prevention Of Infection ◽  
Significant Difference ◽  
Tibia Fractures ◽  
Systemic Antibiotics

Abstract Introduction Infection is a major complication of open fractures. Antibiotic-impregnated calcium sulfate (AICS) beads are widely used as an adjuvant to systemic antibiotics. Whilst their efficacy in the secondary prevention of infection is established, we present the first retrospective study evaluating AICS beads in the primary prevention of infection in open fractures. Method 214 open femur and tibia fractures in 207 patients were reviewed over a seven-year period. 148 fractures received only systemic antibiotic prophylaxis. 66 fractures also received AICS beads. The occurrence of acute infection (wound infection and acute osteomyelitis) was recorded, as well as that of long-term complications (chronic osteomyelitis, non-union and death). Results Fractures that received AICS with systemic antibiotics had an overall acute infection rate of 42% (28/66), compared to 43% (63/148) in fractures that received only systemic antibiotics (p > 0.05). There was no significant difference in infection rate even when fractures were stratified by Gustilo-Anderson grade. There was also no significant difference in the rate of long-term complications. Conclusions Our results indicate that the adjuvant use of AICS beads is not effective for the primary prevention of acute infection or long-term complications in open leg fractures. Further research is needed to elucidate the factors influencing the outcomes of AICS use.

scholarly journals Structure-Properties Correlation of Cross-Linked Penicillin G Acylase Crystals

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 451
Author(s):  
Marta Kubiak ◽  
Janine Mayer ◽  
Ingo Kampen ◽  
Carsten Schilde ◽  
Rebekka Biedendieck
Keyword(s):  
Mechanical Stability ◽  
Structural Characteristics ◽  
Penicillin G ◽  
Bacillus Species ◽  
Diffusion Limitations ◽  
Small Water ◽  
Long Term Stability ◽  
Atomic Force ◽  
First Time

In biocatalytic processes, the use of free enzymes is often limited due to the lack of long-term stability and reusability. To counteract this, enzymes can be crystallized and then immobilized, generating cross-linked enzyme crystals (CLECs). As mechanical stability and activity of CLECs are crucial, different penicillin G acylases (PGAs) from Gram-positive organisms have proven to be promising candidates for industrial production of new semisynthetic antibiotics, which can be crystallized and cross-linked to characterize the resulting CLECs regarding their mechanical and catalytic properties. The greatest hardness and Young’s modulus determined by indentation with an atomic force microscope were observed for CLECs of Bacillus species FJAT-PGA CLECs (26 MPa/1450 MPa), followed by BmPGA (Priestia megaterium PGA, 23 MPa/1170 MPa) and BtPGA CLECs (Bacillus thermotolerans PGA, 11 MPa/614 MPa). In addition, FJAT- and BtPGA CLECs showed up to 20-fold higher volumetric activities compared to BmPGA CLECs. Correlation to structural characteristics indicated that a high solvent content and low number of cross-linking residues might lead to reduced stability. Furthermore, activity seems to be restricted by small water channels due to severe diffusion limitations. To the best of our knowledge, we show for the first time in this study that the entire process chain for the characterization of diverse industrially relevant enzymes can be performed at the microliter scale to discover the most important relationships and limitations.

scholarly journals Exposure to Δ9-tetrahydrocannabinol during rat pregnancy leads to impaired cardiac dysfunction in postnatal life

2021 ◽  
Author(s):  
Kendrick Lee ◽  
Steven R. Laviolette ◽  
Daniel B. Hardy
Keyword(s):  
Body Weight ◽  
Cardiac Function ◽  
Cardiac Dysfunction ◽  
Cardiac Remodelling ◽  
Long Term Effects ◽  
Catch Up ◽  
First Time ◽  
Impaired Cardiac Function ◽  
In Pregnancy

Abstract Background Cannabis use in pregnancy leads to fetal growth restriction (FGR), but the long-term effects on cardiac function in the offspring are unknown, despite the fact that fetal growth deficits are associated with an increased risk of developing postnatal cardiovascular disease. We hypothesize that maternal exposure to Δ9-tetrahydrocannabinol (Δ9-THC) during pregnancy will impair fetal development, leading to cardiac dysfunction in the offspring. Methods Pregnant Wistar rats were randomly selected and administered 3 mg/kg of Δ9-THC or saline as a vehicle daily via intraperitoneal injection from gestational days 6 to 22, followed by echocardiogram analysis of cardiac function on offspring at postnatal days 1 and 21. Heart tissue was harvested from the offspring at 3 weeks for molecular analysis of cardiac remodelling. Results Exposure to Δ9-THC during pregnancy led to FGR with a significant decrease in heart-to-body weight ratios at birth. By 3 weeks, pups exhibited catch-up growth associated with significantly greater left ventricle anterior wall thickness with a decrease in cardiac output. Moreover, these Δ9-THC-exposed offsprings exhibited increased expression of collagen I and III, decreased matrix metallopeptidase-2 expression, and increased inactivation of glycogen synthase kinase-3β, all associated with cardiac remodelling. Conclusions Collectively, these data suggest that Δ9-THC-exposed FGR offspring undergo postnatal catch-up growth concomitant with cardiac remodelling and impaired cardiac function early in life. Impact To date, the long-term effects of perinatal Δ9-THC (the main psychoactive component) exposure on the cardiac function in the offspring remain unknown. We demonstrated, for the first time, that exposure to Δ9-THC alone during rat pregnancy results in significantly smaller hearts relative to body weight. These Δ9-THC-exposed offsprings exhibited postnatal catch-up growth concomitant with cardiac remodelling and impaired cardiac function. Given the increased popularity of cannabis use in pregnancy along with rising Δ9-THC concentrations, this study, for the first time, identifies the risk of perinatal Δ9-THC exposure on early postnatal cardiovascular health.

Empowering and Directive Leadership: The Cost of Changing Styles

2021 ◽  
pp. 227853372110083
Author(s):  
Smita Mukherjee ◽  
Zubin R. Mulla
Keyword(s):  
Laboratory Experiment ◽  
Leadership Styles ◽  
Leadership Style ◽  
Affective Commitment ◽  
Team Outcomes ◽  
History Of ◽  
Satisfaction With The Leader ◽  
The Cost ◽  
First Time

We examine the cost of leaders changing between empowering and directive leadership styles on team outcomes. In a laboratory experiment, we collected data from 240 participants in 80 teams. Confederates enacted different leadership styles and led teams of participants in performing a series of tasks. When leaders changed their style from directive to empowering, teams took time to respond in terms of higher satisfaction with leader and affective commitment. However, when leaders changed their style from empowering to directive, the deterioration of satisfaction with leader and reduction in affective commitment were immediate. Moreover, teams of leaders who had been consistently directive showed higher affective commitment as compared to teams of leaders who had a history of being empowering but later shifted to being directive. First time managers can get inputs on how they should enact their leadership style and be aware that switching between styles may impose long-term costs on the team’s affective commitment and satisfaction with the leader.

scholarly journals Solubility Product of Vanadinite Pb5(VO4)3Cl at 25 °C—A Comprehensive Approach to Incongruent Dissolution Modeling

Minerals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 135
Author(s):  
Justyna Topolska ◽  
Bartosz Puzio ◽  
Olaf Borkiewicz ◽  
Julia Sordyl ◽  
Maciej Manecki
Keyword(s):  
Nuclear Waste ◽  
Solubility Product ◽  
Geochemical Modeling ◽  
Incongruent Dissolution ◽  
Mineral Solubility ◽  
Actual Application ◽  
Universal Approach ◽  
Solubility Constant ◽  
First Time

Although vanadinite (Pb5(VO4)3Cl) occurs in abundance in various terrestrial geochemical systems of natural and anthropogenic origin and is seriously considered as a potential nuclear waste sequestering agent, its actual application is severely limited by a lack of understanding of its basic thermodynamic parameters. In this regard, the greatest challenge is posed by its incongruent dissolution, which is a pivotal hurdle for effective geochemical modeling. Our paper presents an universal approach for geochemical computing of systems undergoing incongruent dissolution which, along with unique, long-term experiments on vanadinites’ stability, allowed us to determine the mineral solubility constant. The dissolution experiments were carried out at pH = 3.5 for 12 years. Vanadinite has dissolved incongruently, continuously re-precipitating into chervetite (Pb2V2O7) with the two minerals remaining in mutual equilibrium until termination of the experiments. The empirically derived solubility constant Ksp,V,298 = 10–91.89 ± 0.05 of vanadinite was determined for the first time. The proposed modeling method is versatile and can be adopted to other mineral systems undergoing incongruent dissolution.

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