Competition in variable environments: experiments with planktonic rotifers

2002 ◽  
Vol 47 (6) ◽  
pp. 1089-1096 ◽  
Author(s):  
KEVIN L. KIRK
Author(s):  
Andrew C. Dragunas ◽  
Tara Cornwell ◽  
Roberto Lopez-Rosado ◽  
Keith E. Gordon

2012 ◽  
Vol 42 (5) ◽  
pp. 970-985 ◽  
Author(s):  
Ola Ringdahl ◽  
Thomas Hellström ◽  
Ola Lindroos

In conventional mechanized cut-to-length systems, a harvester fells and cuts trees into logs that are stored on the ground until a forwarder picks them up and carries them to landing sites. A proposed improvement is to place logs directly into the load spaces of transporting machines as they are cut. Such integrated loading could result in cost reductions, shorter lead times from stump to landing, and lower fuel consumption. However, it might also create waiting times for the machines involved, whereas multifunctional machines are likely to be expensive. Thus, it is important to analyze whether or not the advantages of any changes outweigh the disadvantages. The conventional system was compared with four potential systems, including two with autonomous forwarders, using discrete-event simulation with stochastic elements in which harvests of more than 1000 final felling stands (containing in total 1.6 million m3) were simulated 35 times per system. The results indicate that harwarders have substantial potential (less expensive on ≥80% of the volume and fuel consumption decreased by ≥18%) and may become competitive if key innovations are developed. Systems with cooperating machines have considerably less potential, limited to very specific stand conditions. The results conform with expected difficulties in integrating processing and transporting machines’ work in variable environments.


Agronomy ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 86 ◽  
Author(s):  
Alexey Morgounov ◽  
Yaşar Karaduman ◽  
Beyhan Akin ◽  
Sinan Aydogan ◽  
Peter Stephen Baenziger ◽  
...  

Breeding programs for purple wheat are underway in many countries but there is a lack of information on the effects of Pp (purple pericarp) genes on agronomic and quality traits in variable environments and along the product chain (grain-flour-bread). This study was based on unique material: two pairs of isogenic lines in a spring wheat cv. Saratovskaya-29 (S29) background differing only in Pp genes and grain color. In 2017, seven experiments were conducted in Kazakhstan, Russia, and Turkey with a focus on genotype and environment interaction and, in 2018, one experiment in Turkey with a focus on grain, flour, and bread quality. The effect of environment was greater compared to genotype for the productivity and quality traits studied. Nevertheless, several important traits, such as grain color and anthocyanin content, are closely controlled by genotype, offering the opportunity for selection. Phenolic content in purple-grained lines was not significantly higher in whole wheat flour than in red-colored lines. However, this trait was significantly higher in bread. For antioxidant activities, no differences between the genotypes were detected in both experiments. Comparison of two sources of Pp genes demonstrated that the lines originating from cv. Purple Feed had substantially improved productivity and quality traits compared to those from cv. Purple.


2017 ◽  
Vol 28 (6) ◽  
pp. 1423-1434 ◽  
Author(s):  
Lisa Jacquin ◽  
Zoé Gauthey ◽  
Vincent Roussille ◽  
Michel Le Hénaff ◽  
Cédric Tentelier ◽  
...  

Hydrobiologia ◽  
1992 ◽  
Vol 232 (2) ◽  
pp. 133-143 ◽  
Author(s):  
S. Neumann-Leit�o ◽  
M. N. Paranagu� ◽  
J. L. Valentin
Keyword(s):  

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