scholarly journals Feedback between environment and traits under selection in a seasonal environment: consequences for experimental evolution

2018 ◽  
Vol 285 (1876) ◽  
pp. 20180284 ◽  
Author(s):  
Dorian Collot ◽  
Thibault Nidelet ◽  
Johan Ramsayer ◽  
Olivier C. Martin ◽  
Sylvie Méléard ◽  
...  
Keyword(s):  
Experimental Evolution ◽  
Life History Traits ◽  
Environmental Changes ◽  
Strong Impact ◽  
Fitness Components ◽  
Batch Cultures ◽  
Seasonal Environment ◽  
Different Seasons ◽  
Using Data ◽  
The Impact

Batch cultures are frequently used in experimental evolution to study the dynamics of adaptation. Although they are generally considered to simply drive a growth rate increase, other fitness components can also be selected for. Indeed, recurrent batches form a seasonal environment where different phases repeat periodically and different traits can be under selection in the different seasons. Moreover, the system being closed, organisms may have a strong impact on the environment. Thus, the study of adaptation should take into account the environment and eco-evolutionary feedbacks. Using data from an experimental evolution on yeast Saccharomyces cerevisiae , we developed a mathematical model to understand which traits are under selection, and what is the impact of the environment for selection in a batch culture. We showed that two kinds of traits are under selection in seasonal environments: life-history traits, related to growth and mortality, but also transition traits, related to the ability to react to environmental changes. The impact of environmental conditions can be summarized by the length of the different seasons which weight selection on each trait: the longer a season is, the higher the selection on associated traits. Since phenotypes drive season length, eco-evolutionary feedbacks emerge. Our results show how evolution in successive batches can affect season lengths and strength of selection on different traits.

Changes in soil properties on agricultural land with the impact of water and tillage erosion in the last 60 years

2020 ◽  
Author(s):  
Anna Juřicová ◽  
Tomáš Chuman ◽  
Daniel Žížala
Keyword(s):  
Spatial Variability ◽  
Soil Properties ◽  
Large Scale ◽  
Agricultural Land ◽  
Environmental Changes ◽  
Soil Depth ◽  
Field Investigation ◽  
Strong Impact ◽  
The Impact ◽  
Tillage Erosion

<p>The decline in soil organic carbon (SOC) is generally perceived as a major threat to the sustainability of the soil due to its key role in many productive and non - productive soil functions. The aim of this research is to assess the intensity of changes and the spatial variability of SOC and soil depth in the last 60 years. Estimation of spatial variability of soil properties was performed by using digital soil mapping. A study area is located in the chernozems area in south Moravia (Czechia). This region is traditionally intensively cultivated with the strong impact of water and tillage erosion. The study is based on the analysis of historical data that comes from the Large-scale mapping of Agricultural Soils in Czechoslovakia soil database. Our dataset contained data from 120 soil profiles. A new field investigation shows significant SOC losses on steep slopes and slope shoulders with a decrease of depth of the humic horizon. As a result, there is a gradual transformation of soil units from the former Calcic Chernosems into the Haplic Calcisols. These findings are the result of ongoing environmental changes with the strong impact of historical agricultural policy and inappropriate interference in the landscape.</p>

scholarly journals Impact of NaCl, nitrate and temperature on the microbial community of a methanol-fed, denitrifying marine biofilm

2019 ◽  
Author(s):  
Richard Villemur ◽  
Geneviève Payette ◽  
Valérie Geoffroy ◽  
Florian Mauffrey ◽  
Christine Martineau
Keyword(s):  
Microbial Community ◽  
Environmental Changes ◽  
Heterotrophic Bacteria ◽  
Denitrifying Bacteria ◽  
Metagenomic Data ◽  
Strong Impact ◽  
Anoxic Conditions ◽  
Pure Cultures ◽  
Denitrification Genes ◽  
The Impact

AbstractBackgroundThe biofilm of a continuous, methanol-fed, fluidized denitrification system that treated a marine effluent at the Montreal Biodome is composed of a multi-species microbial community, among whichHyphomicrobium nitrativoransNL23 andMethylophaga nitratireducenticrescensJAM1 are the principal bacteria involved in the denitrifying activities. To assess its resilience to environmental changes, the biofilm taken from the denitrification system was cultured at laboratory scale in artificial seawater (ASW) under anoxic conditions and exposed to a range of specific physico-chemical parameters. We previously showed that the seawater formulation and the NaCl concentrations had a strong impact on theH. nitrativoransNL23 population, with its displacement by a new denitrifier,M. nitratireducenticrescensGP59. Here, we report the impact of these cultures conditions on the dynamics of the overall microbial community of the denitrifying biofilm.MethodsThe original biofilm (OB) taken from the denitrification system was acclimated for five weeks in ASW under anoxic conditions with a range of NaCl concentrations, and with four combinations of nitrate concentrations and temperatures. The OB was also acclimated to the commercial Instant Ocean seawater medium (IO). The bacterial diversity of the biofilm cultures and the OB was determined by 16S ribosomal RNA amplicon metagenome sequencing. Culture-dependent approach was used to isolate other denitrifying bacteria from the biofilm cultures. The metatranscriptomes of some of the biofilm cultures were derived, along with the transcriptomes of planktonic pure cultures ofH. nitrativoransNL23 andM. nitratireducentricrescensGP59 cultivated under denitrifying conditions.ResultsThe 16S metagenomic data revealed very high proportions ofM. nitratireducenticrescensin the biofilm cultures.H. nitrativoransNL23 was found in high proportion in the OB, both was absent in the biofilm cultures with 2.75% NaCl in the ASW medium. It was found however in low proportions in the biofilm cultures with 0 to 1% NaCl in the ASW medium and in the IO biofilm cultures. Emergence ofMarinicellaspp. occurred in these biofilm cultures. Denitrifying bacterial isolates affiliated toMarinobacterspp. andParacoccusspp. were isolated. Up regulation of the denitrification genes in strains GP59 and NL23 occurred in the biofilm cultures compared to the planktonic pure cultures. Denitrifying bacteria affiliated to theStappiaspp. were metabolically active in the biofilm cultures.ConclusionsThese results illustrate the dynamics of the microbial community in the denitrifying biofilm cultures in adapting to different environmental conditions. The NaCl concentration is an important factor affecting the microbial community in the biofilm cultures. Up regulation of the denitrification genes in strain GP59 and strain NL23 in the biofilm cultures suggests different mechanisms of regulation of the denitrification pathway in the biofilm compared to the planktonic pure cultures. Other denitrifying heterotrophic bacteria are present in low proportions in the biofilm, suggesting that the biofilm has the potential to adapt to heterotrophic, non-methylotrophic environments.

scholarly journals Main drivers affecting the Holocene sedimentary record – implications from small lake in Latvia

Baltica ◽  
2016 ◽  
Vol 29 (1) ◽  
pp. 63-78 ◽  
Author(s):  
Jaanus Terasmaa ◽  
Liisa Puusepp ◽  
Egert Vandel ◽  
Agáta Marzecová ◽  
Tiiu Koff ◽  
...  
Keyword(s):  
Environmental Changes ◽  
Climatic Conditions ◽  
Lake Basin ◽  
Strong Impact ◽  
Sedimentary Record ◽  
The Holocene ◽  
Multiple Indicators ◽  
Sediment Mass ◽  
Ground Penetrating ◽  
The Impact

A multi-indicator paleolimnological study of sediments from Lake Ķūži (central Latvia) was used to obtain a comprehensive record of environmental changes in the Holocene. Periodicity in the changes and the main drivers (lake basin development, catchment properties, climate, human activities) of the sedimentary record was studied. In order to comprehend the whole-lake sedimentation during the Holocene, a detailed multiindicator record from the central part of the lake was integrated with records of sediment mass accumulation rates from four cores from different parts of the lake and a GPR (ground-penetrating radar) survey of the lake basin. The observed changes in the sedimentation regime that took place during the early Holocene are strongly linked with variations in climatic conditions, but the catchment and lake basin also played an important role. In the middle Holocene the water level was stable and the lake was influenced by climate mediated through changes in the catchment vegetation. Around 5 000 cal. BP sedimentation pattern changed, and three of the four main drivers made a comparably strong impact on the sedimentary signal. Since 2 000 cal. BP multiple indicators point to a major disturbance clearly related to human activity, which conceals the impact of the natural drivers.

scholarly journals The impact of stock collapse on small-scale fishers’ behavior: evidence from Japan

2018 ◽  
Vol 75 (12) ◽  
pp. 2241-2254 ◽  
Author(s):  
Shoichi Kiyama ◽  
Satoshi Yamazaki
Keyword(s):  
Environmental Changes ◽  
Alternative Form ◽  
Small Scale ◽  
Key Species ◽  
Development Policies ◽  
Management And Development ◽  
Declining Species ◽  
Using Data ◽  
Substantial Decline ◽  
The Impact

Understanding behavioral responses of resource users to environmental changes and incentives created by management systems is imperative to implement effective resource management and development policies. A small-scale mixed fishery in the Maizuru Bay, Japan, provides a natural experiment to evaluate changes in small-scale fishers’ harvesting and targeting behavior over the years that one of the key species in the fishery experienced a collapse of the stock. Using data on individual fishers across the pre- and postcollapse periods, we find that inefficient fishers were forced to shut down or stay idle along with the collapse of the stock, and this behavior led to an increase in the overall efficiency in the production of clams (Venerupis philippinarum). The depletion of the stock, however, imposed a natural constraint on the operation, resulting in a substantial decline in the maximum production achievable by the remaining fishers. We further show that the collapse of the stock not only affected the harvesting behavior against the declining species but also led to the expansion of the fishing capacity and effort to catch other species and the development of aquaculture as an alternative form of fish production in the region.

scholarly journals Study of the Impact of Environmental Pollution on Efficiency and Sustainable Development using Data Envelopment Analysis

MATEMATIKA ◽  
2020 ◽  
Vol 36 (2) ◽  
pp. 157-179
Author(s):  
Hamid Hosseini ◽  
Sara Fanati Rashidi ◽  
Ali Hamzehee
Keyword(s):  
Economic Growth ◽  
Data Envelopment Analysis ◽  
Environmental Changes ◽  
Critical Role ◽  
Data Envelopment ◽  
Undesirable Outputs ◽  
Input And Output ◽  
Decision Making Unit ◽  
Using Data ◽  
The Impact

Environmental changes resulting from industrial activity have been occurring for many years, and with the increasing production of greenhouse gases and other pollutants, these changes have played a critical role in global warming. Nowadays, all countries have become aware of the great importance of attention to the environment alongside economic growth. Therefore, they are all after solutions that would allow maximum economic growth with minimum harm to the environment. In the present study, the environmental efficiency of a given system is evaluated using data envelopment analysis (DEA). For this purpose, the economic and environmental dimensions are taken into consideration for each decision-making unit (DMU), with the condition of having undesirable outputs in the environmental dimension. Then, using the concept of “order of efficiency”, an enhanced DEA method is proposed based on weak and strong disposability axioms, which can be used to compare and rank units with undesirable outputs. Next, the capabilities of the proposed approach are demonstrated through an example involving various industries in Iran. Enhanced DEA not only takes more comprehensive input and output sets into account but also monitors the units based on the principles of sustainability.

Accent Policy and Accent Modification Enterprises as Potential Indicators of Intercultural Power Relations: A Call for an Updated Research Agenda

2013 ◽  
Vol 3 (1) ◽  
pp. 22-33 ◽  
Author(s):  
Brynne D. Ovalle ◽  
Rahul Chakraborty
Keyword(s):  
International Relations ◽  
Identity Construction ◽  
Social Theory ◽  
Power Relations ◽  
Linguistic Diversity ◽  
Cultural Organization ◽  
Using Data ◽  
The Individual ◽  
The Impact ◽  
The Relationship

This article has two purposes: (a) to examine the relationship between intercultural power relations and the widespread practice of accent discrimination and (b) to underscore the ramifications of accent discrimination both for the individual and for global society as a whole. First, authors review social theory regarding language and group identity construction, and then go on to integrate more current studies linking accent bias to sociocultural variables. Authors discuss three examples of intercultural accent discrimination in order to illustrate how this link manifests itself in the broader context of international relations (i.e., how accent discrimination is generated in situations of unequal power) and, using a review of current research, assess the consequences of accent discrimination for the individual. Finally, the article highlights the impact that linguistic discrimination is having on linguistic diversity globally, partially using data from the United Nations Educational, Scientific and Cultural Organization (UNESCO) and partially by offering a potential context for interpreting the emergence of practices that seek to reduce or modify speaker accents.

Interculturalism and the Acceptance of Minority Groups

2020 ◽  
Vol 51 (2) ◽  
pp. 135-140 ◽  
Author(s):  
Maykel Verkuyten ◽  
Kumar Yogeeswaran
Keyword(s):  
Minority Groups ◽  
Psychological Research ◽  
Survey Experiment ◽  
Social Psychological ◽  
Negative Attitudes ◽  
Positive Attitudes ◽  
Social Psychological Research ◽  
Using Data ◽  
The Impact ◽  
Situational Effect

Abstract. Multiculturalism has been criticized and rejected by an increasing number of politicians, and social psychological research has shown that it can lead to outgroup stereotyping, essentialist thinking, and negative attitudes. Interculturalism has been proposed as an alternative diversity ideology, but there is almost no systematic empirical evidence about the impact of interculturalism on the acceptance of migrants and minority groups. Using data from a survey experiment conducted in the Netherlands, we examined the situational effect of promoting interculturalism on acceptance. The results show that for liberals, but not for conservatives, interculturalism leads to more positive attitudes toward immigrant-origin groups and increased willingness to engage in contact, relative to multiculturalism.

International Remittances and Private Healthcare in Kerala, India

2020 ◽  
Vol 17 (3) ◽  
pp. 445-460
Author(s):  
Mohd Imran Khan ◽  
Valatheeswaran C.
Keyword(s):  
Instrumental Variable ◽  
Capital Investment ◽  
Healthcare Expenditure ◽  
Healthcare Services ◽  
Private Healthcare ◽  
International Remittances ◽  
Variable Approach ◽  
Using Data ◽  
The Impact ◽  
Instrumental Variable Approach

The inflow of international remittances to Kerala has been increasing over the last three decades. It has increased the income of recipient households and enabled them to spend more on human capital investment. Using data from the Kerala Migration Survey-2010, this study analyses the impact of remittance receipts on the households’ healthcare expenditure and access to private healthcare in Kerala. This study employs an instrumental variable approach to account for the endogeneity of remittances receipts. The empirical results show that remittance income has a positive and significant impact on households’ healthcare expenditure and access to private healthcare services. After disaggregating the sample into different heterogeneous groups, this study found that remittances have a greater effect on lower-income households and Other Backward Class (OBC) households but not Scheduled Caste (SC) and Scheduled Tribe (ST) households, which remain excluded from reaping the benefit of international migration and remittances.

Static and Dynamic Studies of Gasoline in View of its Octane Number and its Toxic Effect

2013 ◽  
Vol 12 (7) ◽  
pp. 451-459
Author(s):  
Ashraf Yehia El-Naggar ◽  
Mohamed A. Ebiad
Keyword(s):  
Toxic Effect ◽  
Aromatic Hydrocarbons ◽  
Octane Number ◽  
Liquid Fuel ◽  
Positive Impact ◽  
Hydrocarbon Composition ◽  
Different Temperatures ◽  
Different Seasons ◽  
The One ◽  
The Impact

Gasoline come primarily from petroleum cuts, it is the preferred liquid fuel in our lives. Two gasoline samples of octane numbers 91 and 95 from Saudi Arabia petrol stations were studied. This study was achieved at three different temperatures 20oC, 30oC and 50oC representing the change in temperatures of the different seasons of the year. Both the evaporated gases of light aromatic hydrocarbons (BTEX) of gasoline samples inside the tank were subjected to analyze qualitatively and quantitatively via capillary gas chromatography. The detailed hydrocarbon composition and the octane number of the studied gasoline samples were determined using detailed hydrocarbon analyzer. The idea of research is indicating the impact of light aromatic compounds in gasoline on the toxic effect of human and environment on the one hand, and on octane number of gasoline on the other hand. Although the value of octane number will be reduced but this will have a positive impact on the environment as a way to produce clean fuel.

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