Can we understand the simultaneous evolution between economic and informality growth in Africa? A preliminary explanation

2021 ◽  
Author(s):  
Loudi NJOYA
Keyword(s):  
Simultaneous Evolution

Effects of prior environmental conditions on the subsequent uptake and release of carbon dioxide in the light

1971 ◽  
Vol 49 (11) ◽  
pp. 1999-2007 ◽  
Author(s):  
F. C. Steward ◽  
G. H. Craven ◽  
S. P. R. Weerasinghe ◽  
R. G. S. Bidwell
Keyword(s):  
Carbon Dioxide ◽  
Developmental Stage ◽  
Environmental Conditions ◽  
Day Length ◽  
Night Temperature ◽  
Total Uptake ◽  
Short Days ◽  
Simultaneous Evolution ◽  
Uptake And Release

Rates of uptake and simultaneous evolution of carbon dioxide in the light were measured on leaves from various plants by a 14CO2–12CO2 technique under standardized conditions. The measurements were made on leaves from rice, potato, and carrot plants grown under conditions of long or short days combined with high or low night temperatures. The rates of uptake and release of carbon dioxide in the light, and the relationships between them, were affected by the prior conditions that obtained during growth (day length and night temperature), by the age of the leaves, and by the developmental stage of the plants. Since the total uptake of carbon dioxide and its release in the light did not always respond to these variables to the same extent, or even in the same direction, the effectiveness of photosynthesis was often markedly affected. The implications of these observations are, therefore, discussed.

Effect of Al Sputtering Current on Structure of CrAlN Thin Films Prepared by Reactive DC Magnetron Co-Sputtering

2017 ◽  
Vol 866 ◽  
pp. 322-325
Author(s):  
Amonrat Khambun ◽  
Adisorn Buranawong ◽  
Nirun Witit-Anun
Keyword(s):  
Crystal Structure ◽  
Thin Films ◽  
Solid Solution ◽  
Film Thickness ◽  
Elemental Composition ◽  
Cross Section ◽  
Amorphous Structure ◽  
Film Hardness ◽  
Deposited Films ◽  
Simultaneous Evolution

Chromium aluminium nitride (CrAlN) thin films were deposited on Si by reactive DC magnetron co-sputtering technique. The effect of Al sputtering current (IAl) on the crystal structure, elemental composition, thickness, microstructure and hardness were determined by XRD, EDS, AFM and FE-SEM and Nanoindentation, respectively. The results showed that, the as-deposited films were formed as a (Cr,Al)N solid solution with low Al sputtering current, whereas the amorphous structure can be found at high Al sputtering current. The film thickness and roughness was in range of 347 - 1047 nm and 1.45 - 3.37 nm, respectively. The elemental composition of the films varied with the Al sputtering current. The FE-SEM results indicated that the simultaneous evolution in grain refinement with cross-section microstructure through the Al sputtering current. The film hardness increased from 36 GPa to 46 GPa with increasing of Al contents.

scholarly journals Conductivity and phase morphology of carbon black-filled immiscible polymer blends under creep: an experimental and theoretical study

2016 ◽  
Vol 18 (47) ◽  
pp. 32125-32131 ◽  
Author(s):  
Yamin Pan ◽  
Xianhu Liu ◽  
Xiaoqiong Hao ◽  
Dirk W. Schubert
Keyword(s):  
Carbon Black ◽  
Polymer Blends ◽  
Theoretical Study ◽  
Phase Morphology ◽  
Quiescent State ◽  
Immiscible Polymer Blends ◽  
Immiscible Polymer ◽  
Simultaneous Evolution

The simultaneous evolution of conductivity and phase morphology of blend composites was investigated under shear and in the quiescent state.

scholarly journals The simultaneous evolution of author and paper networks

2004 ◽  
Vol 101 (Supplement 1) ◽  
pp. 5266-5273 ◽  
Author(s):  
K. Borner ◽  
J. T. Maru ◽  
R. L. Goldstone
Keyword(s):  
Simultaneous Evolution

Modeling the Simultaneous Evolution of Resistance to ALS- and ACCase-Inhibiting Herbicides in Barnyardgrass (Echinochloa crus-galli) in Clearfield®Rice

2014 ◽  
Vol 28 (1) ◽  
pp. 89-103 ◽  
Author(s):  
Muthukumar V. Bagavathiannan ◽  
Jason K. Norsworthy ◽  
Kenneth L. Smith ◽  
Paul Neve
Keyword(s):  
Weed Management ◽  
Key Management ◽  
Production Systems ◽  
Acetolactate Synthase ◽  
Rice Production ◽  
Management Scenarios ◽  
Management Options ◽  
Evolution Of Resistance ◽  
Clearfield Rice ◽  
Simultaneous Evolution

Herbicide-resistant barnyardgrass has become widespread in the rice production systems of the midsouthern United States, leaving few effective herbicide options for controlling this weed. The acetolactate synthase (ALS)- and acetyl-CoA carboxylase (ACCase)-inhibiting herbicides remain largely effective in Clearfield®rice production, but strategies need to be developed to protect the long-term utility of these options. A two-trait model was developed to understand simultaneous evolution of resistance in barnyardgrass to the ALS- and ACCase-inhibiting herbicides in Clearfield rice. The model was used to predict resistance under a number of common weed management scenarios across 1,000 hypothetical rice fields in the Mississippi Delta region and answer some key management questions. Under an ALS inhibitor–only program consisting of three annual applications of imidazolinone herbicides (imazethapyr or imazamox) in continuous Clearfield rice, resistance was predicted within 4 yr with 80% risk by year 30. Weed management programs that consisted of ALS- and ACCase-inhibiting herbicides such as fenoxaprop and cyhalofop greatly reduced the risk of ALS-inhibiting herbicide resistance (12% risk by year 30), but there was a considerable risk for ACCase resistance (evolving by year 14 with 13% risk by year 30) and multiple resistance (evolving by year 16 with 11% risk by year 30) to both of these mechanisms of action. A unique insight was that failure to stop using a herbicide soon after resistance evolution can accelerate resistance to the subsequent herbicide option. Further, a strong emphasis on minimizing seedbank size is vital for any successful weed management strategy. Results also demonstrated that diversifying management options is not just adequate, but diversity combined with timely herbicide applications aimed at achieving high efficacy levels possible is imperative.

scholarly journals Speciation: more likely through a genetic or through a learned habitat preference?

2005 ◽  
Vol 272 (1571) ◽  
pp. 1455-1463 ◽  
Author(s):  
J.B Beltman ◽  
J.A.J Metz
Keyword(s):  
Reproductive Isolation ◽  
Habitat Preference ◽  
Sympatric Speciation ◽  
Genetic Mechanism ◽  
Dynamical Analysis ◽  
Disruptive Selection ◽  
Single Population ◽  
Preferred Habitat ◽  
Simultaneous Evolution ◽  
Evolution Proceeds

A problem in understanding sympatric speciation is establishing how reproductive isolation can arise when there is disruptive selection on an ecological trait. One of the solutions that has been proposed is that a habitat preference evolves, and that mates are chosen within the preferred habitat. We present a model where the habitat preference can evolve either by means of a genetic mechanism or by means of learning. Employing an adaptive-dynamical analysis, we show that evolution proceeds either to a single population of specialists with a genetic preference for their optimal habitat, or to a population of generalists without a habitat preference. The generalist population subsequently experiences disruptive selection. Learning promotes speciation because it increases the intensity of disruptive selection. An individual-based version of the model shows that, when loci are completely unlinked and learning confers little cost, the presence of disruptive selection most probably leads to speciation via the simultaneous evolution of a learned habitat preference. For high costs of learning, speciation is most likely to occur via the evolution of a genetic habitat preference. However, the latter only happens when the effect of mutations is large, or when there is linkage between genes coding for the different traits.

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