scholarly journals Understanding the impacts of binary additives on mechanical and morphological response of ameliorated soil for road infrastructures

Author(s):  
Imoh Christopher Attah ◽  
Roland Kufre Etim ◽  
David Ufot Ekpo ◽  
Kennedy Chibuzor Onyelowe
1999 ◽  
Vol 40 (3) ◽  
pp. 233-240 ◽  
Author(s):  
S. G. T. Giovannini ◽  
D. M. L. da Motta Marques

The behavior of three emergent aquatic macrophytes under different water regimes was studied with the aim of achieving reconvertion of degraded wetlands and wetland construction for water quality improvement. Scirpus californicus, Typha subulata and Zizaniopsis bonariensis establishment was evaluated under a split plot design, in a factorial experiment with three levels of a water regime factor over a subsoil substratum. The stagnant 10±2 cm water level was best suited to T. subulata and Z. bonariensis development and S. californicus developed better at oscillating water level (3±2 cm) with flooding at 48 hour intervals. The morphological response variables (thickness and width at half length of the tallest leaf or stem per plant, height of tallest leaf or stem per plant, number of green leaves or stems and number of shoots per plant, and survival of propagules' original leaves or stems) were satisfactory descriptors to differentiate (p<0.1%) growth of above ground parts as related to water regimes and species. The three species did survive satisfactory in subsoil-like substratum under the tested water regimes. Mortality was in the worse case, 17.2%, 36.7%, and 9.4% for S. californicus, T. subulata, and Z. bonariensis, respectively. Although Z. bonariensis growth was very poor, only S. californicus and T. subulata could be indicated for planting under similar limiting conditions.


Geosciences ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 253
Author(s):  
Tomáš Galia

Mountain headwater streams are still somewhat on the boundary of interest regarding possible human impact on their morphology or geomorphic processes, which may be caused by our perception of mountains as islands of relatively preserved natural conditions. This paper summarizes the past and present human pressure on the headwater streams that drain the highest mountain ranges of the Outer Western Carpathians in Czechia. Anthropogenic pressure began in this region in the 16th century during a colonization of the mountains and continued by timber harvesting, timber floating, and construction of torrent control works until present. Each of these interventions produced a morphological response of the channels in relation to altered sediment or water fluxes at the whole catchment scale or within longitudinal stream profiles. Because it is highly unlikely to reach pre-settlement conditions of the channels, the management effort should be concentrated to achieve realistic restoration targets under the present socioeconomic circumstances by taking into consideration the morphodynamical specifics of mountain headwater streams.


Genetics ◽  
1998 ◽  
Vol 149 (2) ◽  
pp. 795-805
Author(s):  
Jinah Kim ◽  
Jeanne P Hirsch

Abstract SSF1 and SSF2 are redundant essential yeast genes that, when overexpressed, increase the mating efficiency of cells containing a defective Ste4p Gβ subunit. To identify the precise function of these genes in mating, different responses to pheromone were assayed in cells that either lacked or overexpressed SSF gene products. Cells containing null alleles of both SSF1 and SSF2 displayed the normal transcriptional induction response to pheromone but were unable to form mating projections. Overexpression of SSF1 conferred the ability to form mating projections on cells containing a temperature-sensitive STE4 allele, but had only a small effect on transcriptional induction. SSF1 overexpression preferentially increased the mating efficiency of a strain containing a null allele of SPA2, a gene that functions specifically in cell morphology. To investigate whether Ssf1p plays a direct physical role in mating projection formation, its subcellular location was determined. An Ssf1p-GFP fusion was found to localize to the nucleolus, implying that the role of SSF gene products in projection formation is indirect. The region of Ssf1p-GFP localization in cells undergoing projection formation was larger and more diffuse, and was often present in a specific orientation with respect to the projection. Although the function of Ssf1p appears to originate in the nucleus, it is likely that it ultimately acts on one or more of the proteins that is directly involved in the morphological response to pheromone. Because many of the proteins required for projection formation during mating are also required for bud formation during vegetative growth, regulation of the activity or amount of one or more of these proteins by Ssf1p could explain its role in both mating and dividing cells.


2011 ◽  
Vol 55 (11) ◽  
pp. 5099-5106 ◽  
Author(s):  
Scott S. Walker ◽  
Yiming Xu ◽  
Ilias Triantafyllou ◽  
Michelle F. Waldman ◽  
Cara Mendrick ◽  
...  

ABSTRACTThe echinocandins are a class of semisynthetic natural products that target β-1,3-glucan synthase (GS). Their proven clinical efficacy combined with minimal safety issues has made the echinocandins an important asset in the management of fungal infection in a variety of patient populations. However, the echinocandins are delivered only parenterally. A screen for antifungal bioactivities combined with mechanism-of-action studies identified a class of piperazinyl-pyridazinones that target GS. The compounds exhibitedin vitroactivity comparable, and in some cases superior, to that of the echinocandins. The compounds inhibit GSin vitro, and there was a strong correlation between enzyme inhibition andin vitroantifungal activity. In addition, like the echinocandins, the compounds caused a leakage of cytoplasmic contents from yeast and produced a morphological response in molds characteristic of GS inhibitors. Spontaneous mutants ofSaccharomyces cerevisiaewith reduced susceptibility to the piperazinyl-pyridazinones had substitutions inFKS1. The sites of these substitutions were distinct from those conferring resistance to echinocandins; likewise, echinocandin-resistant isolates remained susceptible to the test compounds. Finally, we present efficacy and pharmacokinetic data on an example of the piperazinyl-pyridazinone compounds that demonstrated efficacy in a murine model ofCandida glabratainfection.


2014 ◽  
Vol 74 (12) ◽  
pp. 1243-1254 ◽  
Author(s):  
Rocío Jiménez Alfonso ◽  
Irantzu Gorroño-Etxebarria ◽  
Miriam Rabano ◽  
Maria dM. Vivanco ◽  
Robert Kypta

1991 ◽  
Vol 69 (1) ◽  
pp. 34-38 ◽  
Author(s):  
M. Pigliucci ◽  
M. G. Politi ◽  
D. Bellincampi

Implications of phenotypic plasticity in a subspecific numerical taxonomic study of Ornithogalum montanum Cyr. (Liliaceae) are discussed. Clones belonging to six natural populations were grown in a glasshouse, and their morphological response to three water dosages was analyzed by means of principal component analysis. PC-1 ranks the three groups of replicated populations, suggesting a high degree of phenotypic plasticity; on the other hand, PC-3 is almost environmentally independent. Proximities in the phenetic space are shown to be at least partially environmentally dependent, suggesting a reaction norm for the character correlation matrix. The results do not corroborate a previous recognition of six subspecies of O. montanum. Key words: phenotypic plasticity, numerical taxonomy, Ornithogalum, reaction norm, principal component analysis.


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