scholarly journals Experimental demonstration of floral allocation costs in Crepis tectorum

2006 ◽  
Vol 84 (6) ◽  
pp. 904-909 ◽  
Author(s):  
Stefan Andersson

Information on floral resource costs is fundamental for understanding how selection operates on floral morphology. In this study, I explored the cost of maturing flowers in a self-incompatible population of the ligulate composite Crepis tectorum L. by experimentally manipulating floral investment and then monitoring the response in reproductive effort. Plants on which the heads were removed during the initial stage of ligule expansion had a higher reproductive effort than plants whose heads were removed immediately after flower maturation, and the latter plants had a higher reproductive effort than plants on which all flowers were permitted to set fruit. Judging from biomass estimates and the magnitude of the observed tradeoffs, the amount of resources allocated to maturing flowers was about half as great as the amount of resources devoted to fruit maturation. These and other results suggest that floral tradeoffs may exert negative selection on floral size variables.

2013 ◽  
Vol 10 (4) ◽  
pp. 333-354 ◽  
Author(s):  
Alexandra Aragão

The European water directive forced the Member States to rethink the regulation of water services. Water pricing is now guided by the cost recovery principle. The costs to take into account are manly the environmental and resource costs, but also the financial ones. Portugal was no exception. The evolution from a heavily subsidized activity to a business bound by the polluter pays principle required fast changes and a somewhat difficult adaptation both of economic agents and households.


2016 ◽  
Vol 3 (10) ◽  
pp. 160406 ◽  
Author(s):  
Gil Iosilevskii ◽  
Yannis P. Papastamatiou

Sharks have a distinctive shape that remained practically unchanged through hundreds of millions of years of evolution. Nonetheless, there are variations of this shape that vary between and within species. We attempt to explain these variations by examining the partial derivatives of the cost of transport of a generic shark with respect to buoyancy, span and chord of its pectoral fins, length, girth and body temperature. Our analysis predicts an intricate relation between these parameters, suggesting that ectothermic species residing in cooler temperatures must either have longer pectoral fins and/or be more buoyant in order to maintain swimming performance. It also suggests that, in general, the buoyancy must increase with size, and therefore, there must be ontogenetic changes within a species, with individuals getting more buoyant as they grow. Pelagic species seem to have near optimally sized fins (which minimize the cost of transport), but the majority of reef sharks could have reduced the cost of transport by increasing the size of their fins. The fact that they do not implies negative selection, probably owing to decreased manoeuvrability in confined spaces (e.g. foraging on a reef).


2021 ◽  
Author(s):  
Lyudmila Babenko ◽  
◽  
Valentina Vasilyeva ◽  
Еlena Коnovalova ◽  
◽  
...  

In the course of research it has been stated that the category of «inventories» is not only the object of accounting, but also the object of management, so the identification of inventories in the assets upon receipt at the enterprise is the initial stage of the accounting process. The process of material and technical base management begins at the stage of searching for suppliers, delivery conditions, formation of the logistics component, determination of transport and procurement costs. There is no doubt that the additional costs associated with these processes will affect the formation of the value of purchased inventories. Therefore, the authors emphasize that the methods of estimating inventories at their receipt and disposal play an important role in accounting, as they affect the formation of the cost of finished goods produced from inventories, and hence the overall financial performance of the enterprise. It should also be taken into account that in accordance with the norms of UAS 9, only the amounts of transportation and procurement costs related to the acquisition (receipt) of inventories are subject to inclusion in the initial cost. In practice, the increase in the value of inventories often includes costs incurred in connection with the internal transportation of inventories on the territory of the enterprise or between its structural units; costs arising from the return of inventories to the supplier; costs for loading, transportation, transshipment and insurance of inventories, finished products (goods), freight forwarding and other services related to the sale of products (goods). Such costs do not affect the formation of the initial cost of inventories. Therefore, the authors highlighted the need for a clear delineation of these costs at specific enterprises with the reflection of provisions in the Order (Regulation) on accounting policies. Most scientists discuss the feasibility of search for a method of cost allocation during transportation, because during this process there can be losses of inventories both within the established norms of natural loss, excessive losses and shortages, as well as spoiled inventories found during asset recognition. The authors gave their own view on the possibility of solving this problem. The solving approach has been presented as well as the peculiarities of the reflection of the distributed transport and procurement costs in the system of accounting have been considered. The situation when the company transport both purchased inventories and those, sold to customers, with its own transport has been considered. In such cases, the authors suggest a method of allocating transportation costs with subsequent allocation to transport and procurement costs, which increase the cost of purchased inventories and distribution costs.


2017 ◽  
Vol 30 (1) ◽  
pp. e23069 ◽  
Author(s):  
Anna Ziomkiewicz ◽  
Amara Frumkin ◽  
Yawei Zhang ◽  
Amelia Sancilio ◽  
Richard G. Bribiescas

2020 ◽  
Vol 12 (6) ◽  
pp. 2432 ◽  
Author(s):  
Shabtai Isaac ◽  
Slava Shubin ◽  
Gad Rabinowitz

The objective of this research is to study the cost of Net Zero Energy (NZE) communities of different urban scales and densities, while taking into consideration the local climate and the type of buildings in the community. A comprehensive model was developed for this purpose, with which the cost-optimal configuration of renewable energy-related technologies for an NZE community can be identified. To validate the model, data from two case studies that differed in their climate and building types were used. The results of this study contribute to a better understanding of the implications of NZE requirements for urban planning. An increase in the scale of a community was found to reduce energy costs, up to a certain point. Urban density, on the other hand, was found to have a more complex impact on costs, which depends on the local climate of the community and the subsequent energy demand. This underlines the importance of addressing the technological design of energy systems at the initial stage of the urban planning of energy-efficient communities, before the urban density, the unbuilt areas and the building types are set.


1988 ◽  
Vol 66 (8) ◽  
pp. 1906-1912 ◽  
Author(s):  
Todd W. Arnold

Recently, Zammuto (R. M. Zammuto. 1986. Can. J. Zool. 64: 2739–2749) suggested that North American game birds exhibited survival–fecundity trade-offs consistent with the "cost of reproduction" hypothesis. However, there were four serious problems with the data and the analyses that Zammuto used: (i) the species chosen for analysis ("game birds") showed little taxonomic or ecological uniformity, (ii) the measures of future reproductive value (maximum longevity) were severely biased by unequal sample sizes of band recoveries, (iii) the measures of current reproductive effort (clutch sizes) were inappropriate given that most of the birds analyzed produce self-feeding precocial offspring, and (iv) the statistical units used in the majority of analyses (species) were not statistically independent with respect to higher level taxonomy. After correcting these problems, I found little evidence of survival–fecundity trade-offs among precocial game birds, and I attribute most of the explainable variation in life-history traits of these birds to allometry, phylogeny, and geography.


In implementing fracture mechanics based techniques for the design and life extension of structural components, it is necessary to establish the reliability with which various flaw sizes and types can be detected and characterized. Traditionally, this has been accomplished through extensive experimental demonstration programmes. This paper discusses present efforts to use model predictions to reduce the required amount of experimentation, and hence the cost, of such programmes. Formalisms whereby the extensive elastic-wave theoretical scattering effort of the last decade can be applied to practical problems are first reviewed. This is followed by several specific examples which have occurred in the nuclear and aerospace industries. The paper concludes with the identification of some important remaining theoretical problems and a discussion of possible strategies for future implementation of model calculations as tools in structural integrity programmes.


1988 ◽  
Vol 2 (2) ◽  
pp. 263-265 ◽  
Author(s):  
Uri Yechiali

N tasks must be successfully performed for a job to be completed. The tasks may be attempted in any order, where each attempt of task i requires an expected cost ci and is successful with probability pi. Whenever an attempt fails, the job is fed back to the initial stage and the entire sequence starts again. We show that the cost of completing a job is minimized if the tasks are sequenced via increasing values of ci/(l–pi). We further show that the same result holds when the feedback can be either to stage i itself or to the starting task.


PLoS ONE ◽  
2016 ◽  
Vol 11 (1) ◽  
pp. e0145753 ◽  
Author(s):  
Anna Ziomkiewicz ◽  
Amelia Sancilio ◽  
Andrzej Galbarczyk ◽  
Magdalena Klimek ◽  
Grazyna Jasienska ◽  
...  

1995 ◽  
Vol 73 (10) ◽  
pp. 1683-1686 ◽  
Author(s):  
Angela M. Muir

The cost of reproduction to the clonal understorey herb Asarum canadense (wild ginger) was examined by measuring subsequent growth and storage. All connected vegetative rhizome was controlled and fully measured. Three important aspects of reproductive effort were addressed: (i) the effect of sexual reproduction on subsequent storage and growth of fragments, (ii) the effect of asexual reproduction on subsequent storage and growth of fragments, and (iii) a comparison to determine the least costly method of reproduction. It was found that sexual reproduction in wild ginger has an energy cost that diverts energy from storage and growth. Asexual reproduction represents neither a net energy cost nor gain to the fragment and is the least costly mode of reproduction to wild ginger. Key words: Asarum canadense, reproduction, rhizome, clonal.


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