scholarly journals How competition affects evolutionary rescue

2013 ◽  
Vol 368 (1610) ◽  
pp. 20120085 ◽  
Author(s):  
Matthew Miles Osmond ◽  
Claire de Mazancourt

Populations facing novel environments can persist by adapting. In nature, the ability to adapt and persist will depend on interactions between coexisting individuals. Here we use an adaptive dynamic model to assess how the potential for evolutionary rescue is affected by intra- and interspecific competition. Intraspecific competition (negative density-dependence) lowers abundance, which decreases the supply rate of beneficial mutations, hindering evolutionary rescue. On the other hand, interspecific competition can aid evolutionary rescue when it speeds adaptation by increasing the strength of selection. Our results clarify this point and give an additional requirement: competition must increase selection pressure enough to overcome the negative effect of reduced abundance. We therefore expect evolutionary rescue to be most likely in communities which facilitate rapid niche displacement. Our model, which aligns to previous quantitative and population genetic models in the absence of competition, provides a first analysis of when competitors should help or hinder evolutionary rescue.

2015 ◽  
Author(s):  
Matthew Miles Osmond ◽  
Claire de Mazancourt

Populations facing novel environments can persist by adapting. In nature, the ability to adapt and persist will depend on interactions between coexisting individuals. Here we use an adaptive dynamic model to assess how the potential for evolutionary rescue is affected by intra- and interspecific competition. Intraspecific competition (negative density-dependence) lowers abundance, which decreases the supply rate of beneficial mutations, hindering evolutionary rescue. On the other hand, interspecific competition can aid evolutionary rescue when it speeds adaptation by increasing the strength of selection. Our results clarify this point and give an additional requirement: competition must increase selection pressure enough to overcome the negative effect of reduced abundance. We therefore expect evolutionary rescue to be most likely in communities which facilitate rapid niche displacement. Our model, which aligns to previous quantitative and population genetic models in the absence of competition, provides a first analysis of when competitors should help or hinder evolutionary rescue.


2020 ◽  
Vol 17 (2) ◽  
pp. 172
Author(s):  
HARMAN AGUSAPUTRA ◽  
MARIA SUGENG ◽  
AYLY SOEKAMTO ◽  
ATIK WULANDARI

<p><strong>Abstract</strong></p><p><strong>Background:</strong> Hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) as antiseptic has been used frequently to clean woundsin in hospitals and clinics. Hydrogen peroxide has the effectof strong oxidative that can kill pathogens. It can clean up debris and necrotic tissuesin wounds. Hydrogen peroxidealso has hemostatic effect that can help to stop bleeding. Besides antiseptic effects, hydrogen peroxide i s suspected of having negative effect in wound healing. Hydrogen peroxide presumably could cause delayed wound healing by exudate formation and delayed epithelial growth.</p><p><strong>Method</strong>: This study was conducted in the laboratory using 48 white mice that were divided into 2 groups. All the mice were purposely wounded. Afterwards in one group the wounds were clean up using hydrogen peroxide, while in the other group without hydrogen peroxide as control. The wounds of both groups were observed on day 1, day 3 and day 7. On day 1 and day 3, both groups did not show significant difference.</p><p><strong>R</strong><strong>esult</strong> : on day 7 showed that the wound healing in hydrogen peroxide group were delayed. Fifty percent of them had the formation of exudate and 62.5% of them showed delayed epithelial growth.</p><p><strong>Conclusion </strong>: This study could show hydrogen peroxide as wound antiseptic has delayed wound healing effect.</p><p><strong>Keyword</strong>: hydrogen peroxide, wound healing</p>


2004 ◽  
Vol 5 (2) ◽  
pp. 177-203 ◽  
Author(s):  
Thomas Pfeiffer

Abstract In the literature, the information structure of the hold-up problem is typically assumed to be exogenous. In this paper, we introduce an additional stage at which the head office may grant individual divisions access to an information system before they undertake their specific investments. Although more information ceteris paribus enhances each divisions’ profits, more information can reduce divisions’ investments and destroy synergies for the other division that would have been generated by the investments. If this negative effect dominates, then information can be harmful for the entire company. Hence, information control can be a subtle force to deal with the hold-up problem to a certain extent. In this paper we analyze those conditions under which information is either harmful or beneficial for central management.


2020 ◽  
Vol 3 (1) ◽  
pp. 49
Author(s):  
Edgaras Linkevičius ◽  
Gerda Junevičiūtė

Climate change and warming will potentially have profound effects on forest growth and yield, especially for pure stands in the near future. Thus, increased attention has been paid to mixed stands, e.g., pine and beech mixtures. However, the interaction of tree species growing in mixtures still remains unknown. Thus, the aim of this study was to investigate the impact of the interspecific and intraspecific competition to diameter, height, and crown width of pine and beech trees growing in mixtures, as well as to evaluate the impact of climatic indicators to the beech radial diameter increment. The data was collected in 2017 at the mixed mature pine beech double layer stand, located in the western part of Lithuania. The sample plot of 1.2 hectare was established and tree species, diameter at the breast height, tree height, height-to-crown base, height-to-crown width, and position were measured for all 836 trees. Additionally, a representative sample of radial diameter increments were estimated only for the beech trees by taking out core discs at the height of 1 m when the stand was partially cut. Competition analysis was based on the distance-dependent competition index, which was further based on crown parameters. Climatic effect was evaluated using classification and regression tree (CART) analysis. We found almost no interspecific competition effect to diameter, height, or crown width for both tree species growing in the first layer. However, it had an effect on beeches growing in the second layer. The intraspecific competition effect was important for pine and beech trees, showing a negative effect for both of them. Our results show the possible coexistence of these tree species due to niche differentiation. An analysis of climatic indicators from 1991–2005 revealed that precipitation from February–May of the current vegetation year and mean temperatures from July to September expressed radial diameter increment effects for beech trees. Low temperatures during March and April, as well as high precipitation during January, had a negative effect on beech radial increments. From 2006–2016, the highest effect on radial diameter increments was the mean temperatures from July to September, as well as the precipitation in January of the current year. From 1991–2016, the highest effect on radial diameter increments was the temperature from July to September 1991–2016 and the precipitation in June 1991–2016. Generally, cool temperatures and higher precipitation in June had a positive effect on beech radial increments. Therefore, our results show a sensitivity to high temperatures and droughts during summer amid Lithuanian’s growth conditions.


2003 ◽  
Vol 76 (4) ◽  
pp. 876-891 ◽  
Author(s):  
R. N. Datta ◽  
A. G. Talma ◽  
S. Datta ◽  
P. G. J. Nieuwenhuis ◽  
W. J. Nijenhuis ◽  
...  

Abstract The use of thiurams such as Tetramethyl thiuram disulfide (TMTD) or Tetrabenzyl thiuram disulfide (TBzTD) has been explored to achieve higher cure efficiency. The studies suggest that a clear difference exists between the effect of TMTD versus TBzTD. TMTD reacts with Bis (triethoxysilylpropyl) tetrasulfide (TESPT) and this reaction can take place even at room temperature. On the other hand, the reaction of TBzTD with TESPT is slow and takes place only at higher temperature. High Performance Liquid Chromatography (HPLC) with mass (MS) detection, Nuclear Magnetic Resonance Spectroscopy (NMR) and other analytical tools have been used to understand the differences between the reaction of TMTD and TESPT versus TBzTD and TESPT. The reaction products originating from these reactions are also identified. These studies indicate that unlike TMTD, TBzTD improves the cure efficiency allowing faster cure without significant effect on processing characteristics as well as dynamic properties. The loading of TESPT is reduced in a typical Green tire compound and the negative effect on viscosity is repaired by addition of anhydrides, such as succinic anhydride, maleic anhydride, etc.


2020 ◽  
Vol 4 (1) ◽  
pp. 1-24
Author(s):  
Dinik Fitri Rahajeng Pangestuti ◽  
Nisrina Sari ◽  
Ambar Lestari

Abstract Tax planning is one example of the use of regulatory loopholes. On the other hand for the Fiscal Authority, carrying out tax avoidance practices as a form of tax planning will have a negative effect on the Government and, for this reason, the Government makes fiscal corrections as its remedial. Many also hide their assets in tax heavens countries. This is so that the assets they have are not taxed. Tax heavens countries are usually small countries that apply very low taxes, some even do not impose taxes at all. However, the government has prepared an Automatic Exchange of Information (AEoI) data exchange plan that occurs in 2018, certainly will make tax evaders unable to run away from the pursuit of the tax authorities, even if they have to flee to tax heavens countries (tax heavens). Keywords: tax heavens, tax planning, Automatic Exchange of Information (AEoI)   Abstrak Perencanaan pajak adalah salah satu contoh penggunaan celah peraturan. Pada sisi lain bagi Otoritas Fiskal, melakukan praktik penghindaran pajak sebagai bentuk perencanaan pajak akan membawa efek negatif bagi Pemerintah dan, untuk itulah, Pemerintah melakukan koreksi fiskal sebagai remedialnya. Banyak juga yang menyembunyikan asetnya di negara-negara tax heavens. Hal ini bertujuan agar aset yang mereka punya tidak terkena pajak. Negara tax heavens biasanya merupakan negara kecil yang menerapkan pajak yang sangat rendah, bahkan ada yang tidak mengenakan pajak sama sekali. Namun, pemerintah telah menyiapkan Rencana pertukaran informasi data perbankan secara otomatis (Automatic Exchange of Information/AEoI) yang terjadi pada 2018, dipastikan akan membuat para pengemplang pajak tidak akan bisa lari dari kejaran otoritas pajak, sekalipun mereka harus kabur ke negara surga pajak (tax heavens). Kata kunci: Tax Heavens, Tax Planning, Automatic Exchange of Information (AEoI)


2016 ◽  
Vol 47 (4) ◽  
Author(s):  
Jebur & et al.

This study was aimed to know the efficiency of partially purified L- asparaginase produced from local isolate from Erwinia spp. to reduce the percentage of acrylamide formed in Biscuit. Four types of biscuit from wheat flour were prepared (T1, T2, T3, T4),and T1 as control. High performance liquid chromatography technique was used to estimate acrylamide ratio in biscuit , Effect of enzyme addition  on flour chemical and rheological properties was studied, also dough behavior ,gluten percentage, water absorption and amylase enzyme activity was estimated. The results revealed  that  the  addition of  experimental asparaginase ( specific activity 20.5 unite mg-1 ) with 1% of flour weight lead to reduce in acrylamide formation in Biscuit  to 89 %  compared  to  control sample ( in absence of enzyme ) . Moreover, the addition of Asparagine to flour at 0.1 % of its weight, where L- asparaginase was available caused a negative effect on enzyme efficiency in reducing the acrylamide in biscuit. So the level of acrylamide was reduced to 57.7 %. In the other hand , the percentage of acryl amide in biscuit was increased to   233 % when the asparagine was added to mixture in absence of L- asparaginase .Addition of  the enzyme to flour have no effect on the percentage value of gluten but improved the  stability of dough .The  enzyme  addition also led to increase amylases activities.  Addition of experimental enzyme had no effect on quality and sensory evaluation of biscuit.


1987 ◽  
Vol 44 (1) ◽  
pp. 32-52
Author(s):  
Elizabeth A. Johnson

“Invocation of the saints is a practice which arises as a secondary ramification of certain foundational truths of the Christian faith. To get at the theological intelligibility of how it ‘works’ even today and has the positive effect of evoking reliance on the saving mercy of God, without the negative effect of overshadowing the sole mediatorship of Jesus Christ, two primary insights rooted in the biblical witness need to be considered. One deals with the relation between Jesus Christ and Christian believers, the other with the interrelationship among Christians themselves.”


1979 ◽  
Vol 25 (2) ◽  
pp. 180-203 ◽  
Author(s):  
B. C. Johanson

I Corinthians xiv. 20–25 has long posed severalcruces interpretationisfor commentators. The basic problems concern the relationship of the assertions made about tongues and prophecy in υ. 22 to the quotation of Isa. xxviii. 11–12 in υ. 21 and to the illustrations concerning tongues and prophecy in υυ. 23–5. As to the quotation, J. Ruef remarks that most commentators admit to the difficulty of seeing how it substantiates Paul's conclusion that tongues are meant as a sign for the unbeliever. Concerning the illustrations, both J. Héring and J. P. M. Sweet note that in the light of the assertions we would expect them to be the reverse of what they are. While tongues are asserted to be meant as a sign for unbelievers and prophecy for believers, the illustrations depict the negative effect of tongues upon unbelievers and the positive effect of prophecy not on believers but upon unbelievers. The second assertion (υ. 22b) in particular contradicts the second illustration (υυ. 24–5) in that it clearly states that ‘prophecy is meant as a signnot for unbelieversbut for believers’. This is so if σημεĩον is taken in a positive sense. If, on the other hand, it is taken in a negative sense, the logical relation of this second illustration to the second assertion becomes ambiguous.


Author(s):  
Halima M. ◽  
Sneha Unnikrishnan ◽  
Karthikeyan Ramalingam

Across the globe, in both developed and developing countries, wheat provides the fundamental support for all other important foods. However, due to climate change, environmental stress, soil infertility, etc., the yield of wheat is affected. To overcome these issues, biofertilizers are recommended. They are eco-friendly, cost-efficient, and affordable by marginal farmers too when compared with chemical fertilizers. Biofertilizers are made up of living microorganisms that colonize the rhizosphere to promote plant yield and prevent plant disease. Pesticide degrading strains of bacteria are emerging as the best technique to overcome the negative effect of pesticides. Due to insufficient awareness among farmers, agricultural land and crops are cultivated through chemical fertilizers, which became a major threat to human health and agriculture. On the other hand, the government is implementing several measures in marketing bio-fertilizers for the betterment of agriculture and human health. In this chapter, the significance and future perspectives of biofertilizers have been covered.


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