scholarly journals Long term environmental stability drives reduced stress tolerance in salt lake invertebrates

2021 ◽  
Vol 6 ◽  
pp. 49-64
Author(s):  
James E. O'Dwyer ◽  
Nicholas P. Murphy
Keyword(s):  
Stress Tolerance ◽  
Salt Lake ◽  
Empirical Studies ◽  
Environmental Stability ◽  
Isolated Populations ◽  
Natural Systems ◽  
Physiological Tolerance ◽  
Stabilising Selection ◽  
Extreme Salinity

The capacity of species to tolerate physical stressors is critical in a world of increasing environmental instability, however, past selective environments should dramatically impact on future stress tolerance, particularly in isolated populations. Through stabilising selection, long-term environmental stasis may reduce physiological tolerance, creating an evolutionary legacy where populations are less fit if environments change. Few empirical studies have investigated this evolutionary legacy of past selection, and of particular interest whether stabilising selection in a benign environment reduces stress tolerance in natural systems. Here we use multiple populations of salt-lake invertebrates (Coxiella striata, Austrochiltonia subtenuis) with either stable or fluctuating environmental histories to investigate the relationship between stabilising selection and environmental stress resistance. Tolerance to both salinity and temperature stress were examined in invertebrate populations from lakes with long-term (decadal) stable environments and compared with populations from lakes with extreme salinity variations. Individuals from stable environments demonstrated significantly lower survival under both increasing salinity and temperature stresses when compared with environmentally unstable populations. Our results support the hypothesis that the evolutionary legacy from stabilising selection in constant environments leads to reduced stress tolerance. This finding demonstrates that under an increasingly variable climate, the evolutionary legacies of populations will be critical for future survival and adaptation.

scholarly journals Genomic signatures of inbreeding and genetic load in a threatened rattlesnake

2021 ◽  
Author(s):  
Alexander Ochoa ◽  
H. Lisle Gibbs
Keyword(s):  
Threatened Species ◽  
Empirical Studies ◽  
Genetic Load ◽  
Population History ◽  
Deleterious Mutations ◽  
Genetic Rescue ◽  
Isolated Populations ◽  
Genome Wide ◽  
The Impact

Theory predicts that threatened species living in small populations will experience high levels of inbreeding that will increase their negative genetic load but recent work suggests that the impact of load may be minimized by purging resulting from long term population bottlenecks. Empirical studies that examine this idea using genome-wide estimates of inbreeding and genetic load in threatened species are limited. Here we use genome resequencing data to compare levels of inbreeding, levels of genetic load and population history in threatened Eastern massasauga rattlesnakes (Sistrurus catenatus) which exist in small isolated populations and closely-related yet outbred Western massasauga rattlesnakes (S. tergeminus). In terms of inbreeding, S. catenatus genomes had a greater number of ROHs of varying sizes indicating sustained inbreeding through repeated bottlenecks when compared to S. tergeminus. At the species level, outbred S. tergeminus had higher genome-wide levels of genetic load in the form of greater numbers of derived deleterious mutations compared to S. catenatus presumably due to long-term purging of deleterious mutations in S. catenatus. In contrast, mutations that escaped the “drift sieve” and were polymorphic within S. catenatus populations were more abundant and more often found in homozygote genotypes than in S. tergeminus suggesting a reduced efficiency of purifying selection in smaller S. catenatus populations. Our results support an emerging idea that the historical demography of a threatened species has a significant impact on the type of genetic load present which impacts implementation of conservation actions such as genetic rescue.

Is inflation targeting useful for economic growth?

2017 ◽  
pp. 62-74 ◽  
Author(s):  
P. Kartaev
Keyword(s):  
Economic Growth ◽  
Monetary Policy ◽  
Test Performance ◽  
Inflation Targeting ◽  
Developing Economies ◽  
Empirical Studies ◽  
Growth Regime ◽  
Potential Channels

The paper presents an overview of studies of the effects of inflation targeting on long-term economic growth. We analyze the potential channels of influence, as well as modern empirical studies that test performance of these channels. We compare the effects of different variants of inflation targeting (strict and mixed). Based on the analysis recommendations on the choice of optimal (in terms of stimulating long-term growth) regime of monetary policy in developed and developing economies are formulated.

Paradoxes of reservation wage setting in the Russian labor market. Part I

2016 ◽  
pp. 5-27
Author(s):  
R. Kapeliushnikov ◽  
A. Lukyanova
Keyword(s):  
Labor Market ◽  
Empirical Studies ◽  
Reservation Wage ◽  
Wage Setting ◽  
Reservation Wages ◽  
Monitoring Survey ◽  
Main Determinants ◽  
Subjective Estimates ◽  
Objective Indicators

Using panel data from the Russian Longitudinal Monitoring Survey for 2006-2014, the paper investigates reservation wages setting in the Russian labor market. The sample includes non-employed individuals wishing to get a job (both searchers and non-searchers). The first part of the paper provides a survey of previous empirical studies, describes data and analyzes subjective estimates of reservation wages in comparison with various objective indicators of actual wages. The analysis shows that wage aspirations of the majority of Russian non-employed individuals are overstated. However their wage expectations are rather flexible and decrease rapidly as the search continues that prevents high long-term unemployment. The second part of the paper provides an econometric analysis of main determinants of reservation wage and its impact on probability of re-employment and wages on searchers’ new jobs.

A Note Concerning the Dynamics of Government Bond Yields

2021 ◽  
pp. 056943452098827
Author(s):  
Tanweer Akram
Keyword(s):  
Interest Rate ◽  
Financial Markets ◽  
Yield Curve ◽  
Empirical Studies ◽  
State Theory ◽  
Government Bond ◽  
Bond Yields ◽  
Short Term ◽  
Government Bonds

Keynes argued that the central bank can influence the long-term interest rate on government bonds and the shape of the yield curve mainly through the short-term interest rate. Several recent empirical studies that examine the dynamics of government bond yields not only substantiate Keynes’s view that the long-term interest rate responds markedly to the short-term interest rate but also have relevance for macroeconomic theory and policy. This article relates Keynes’s discussions of money, the state theory of money, financial markets, investors’ expectations, uncertainty, and liquidity preference to the dynamics of government bond yields for countries with monetary sovereignty. Investors’ psychology, herding behavior in financial markets, and uncertainty about the future reinforce the effects of the short-term interest rate and the central bank’s monetary policy actions on the long-term interest rate. JEL classifications: E12; E40; E43; E50; E58; E60; F30; G10; G12; H62; H63

scholarly journals Stability of graphene-based heterojunction solar cells

RSC Advances ◽  
2015 ◽  
Vol 5 (90) ◽  
pp. 73575-73600 ◽  
Author(s):  
Eric Singh ◽  
Hari Singh Nalwa
Keyword(s):  
Solar Cells ◽  
Environmental Stability ◽  
Light Illumination ◽  
Atmospheric Conditions ◽  
Air Humidity ◽  
Heterojunction Solar Cells ◽  
Commercial Applications

The long-term environmental stability and degradation of graphene-based heterojunction solar cells under different atmospheric conditions such as air, humidity, temperature, and light illumination for commercial applications are discussed.

Assessment of needs for care among patients with schizophrenic disorders 15 and 17 years after first onset of psychosis

1997 ◽  
Vol 6 (S1) ◽  
pp. 21-28 ◽  
Author(s):  
Durk Wiersma ◽  
Fokko J. Nienhuis ◽  
Cees J. Slooff ◽  
Robert Giel ◽  
Aant De Jong
Keyword(s):  
Mental Disorders ◽  
Empirical Studies ◽  
Signs And Symptoms ◽  
Expected Improvement ◽  
Chronic Patients ◽  
Cross Sectional ◽  
Wide Range ◽  
Social Disablement ◽  
First Onset

Severe and long term mental disorders, like schizophrenia, show in general a wide range of psychiatric signs and symptoms, psychological and physiological impairments and social disablement (Shepherd, 1994; Wing, 1982) reflecting a variety of mental health needs. Many studies provide only a cross-sectional view of the clinical and social problems of the patient population, for example at intake or admission to a mental hospital. Longitudinal studies following patients after discharge for some period of months or years show in general the expected improvement of functioning (e.g. Nienhuis et al., 1994), but as far as only chronic patients are concerned such a positive change is much less noted. The concept of chronicity of mental disorders would presume that after some time needs are fairly predictable and stable and do not change much over time. Our investigation on the long-term course of schizophrenia (Wiersma et al., 1996; 1997) enables us to study over a period of two years, from 15 to 17 years since first onset of psychosis, the stability or variability of needs in schizophrenic disorder. We are not aware of empirical studies on changes in needs among patients with long-term disorders.

scholarly journals The Great Salt Lake Ecosystem (Utah, USA): long term data and a structural equation approach

Ecosphere ◽  
2011 ◽  
Vol 2 (3) ◽  
pp. art33 ◽  
Author(s):  
Gary E. Belovsky ◽  
Doyle Stephens ◽  
Clay Perschon ◽  
Paul Birdsey ◽  
Don Paul ◽  
...  
Keyword(s):  
Structural Equation ◽  
Salt Lake ◽  
Great Salt Lake ◽  
Lake Ecosystem ◽  
Equation Approach ◽  
Term Data

scholarly journals Long-Term Waterlogging as Factor Contributing to Hypoxia Stress Tolerance Enhancement in Cucumber: Comparative Transcriptome Analysis of Waterlogging Sensitive and Tolerant Accessions

Genes ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 189
Author(s):  
Kinga Kęska ◽  
Michał Wojciech Szcześniak ◽  
Izabela Makałowska ◽  
Małgorzata Czernicka
Keyword(s):  
Stress Tolerance ◽  
De Novo ◽  
Average Length ◽  
Marker Genes ◽  
Long Term Memory ◽  
Low Oxygen ◽  
Waterlogging Tolerance ◽  
Pre Treatment ◽  
Waterlogging Treatment

Waterlogging (WL), excess water in the soil, is a phenomenon often occurring during plant cultivation causing low oxygen levels (hypoxia) in the soil. The aim of this study was to identify candidate genes involved in long-term waterlogging tolerance in cucumber using RNA sequencing. Here, we also determined how waterlogging pre-treatment (priming) influenced long-term memory in WL tolerant (WL-T) and WL sensitive (WL-S) i.e., DH2 and DH4 accessions, respectively. This work uncovered various differentially expressed genes (DEGs) activated in the long-term recovery in both accessions. De novo assembly generated 36,712 transcripts with an average length of 2236 bp. The results revealed that long-term waterlogging had divergent impacts on gene expression in WL-T DH2 and WL-S DH4 cucumber accessions: after 7 days of waterlogging, more DEGs in comparison to control conditions were identified in WL-S DH4 (8927) than in WL-T DH2 (5957). Additionally, 11,619 and 5007 DEGs were identified after a second waterlogging treatment in the WL-S and WL-T accessions, respectively. We identified genes associated with WL in cucumber that were especially related to enhanced glycolysis, adventitious roots development, and amino acid metabolism. qRT-PCR assay for hypoxia marker genes i.e., alcohol dehydrogenase (adh), 1-aminocyclopropane-1-carboxylate oxidase (aco) and long chain acyl-CoA synthetase 6 (lacs6) confirmed differences in response to waterlogging stress between sensitive and tolerant cucumbers and effectiveness of priming to enhance stress tolerance.

Late Quaternary vegetation dynamics in a biodiversity hotspot, the Uluguru Mountains of Tanzania

2009 ◽  
Vol 72 (1) ◽  
pp. 111-122 ◽  
Author(s):  
Jemma Finch ◽  
Melanie J. Leng ◽  
Rob Marchant
Keyword(s):  
Environmental Changes ◽  
Vegetation History ◽  
Late Quaternary ◽  
Anthropogenic Activities ◽  
Significant Loss ◽  
Environmental Stability ◽  
Forest Composition ◽  
Eastern Arc ◽  
Uluguru Mountains

AbstractLate Quaternary vegetation history and environmental changes in a biodiverse tropical ecosystem are inferred from pollen, charcoal and carbon isotope evidence derived from a ∼ 48,000-yr sedimentary record from the Uluguru Mountains, a component of the Eastern Arc Mountains of Kenya and Tanzania. Results indicate that Eastern Arc forest composition has remained relatively stable during the past ∼ 48,000 yr. Long-term environmental stability of the Eastern Arc forests has been proposed as a mechanism for the accumulation and persistence of species during glacial periods, thus resulting in the diverse forests observed today. The pollen and isotope data presented here indicate some marked changes in abundance but no significant loss in moist forest taxa through the last glacial maximum, thereby providing support for the long-term environmental stability of the Eastern Arc. Anthropogenic activities, including burning and forest clearance, were found to play a moderate role in shaping the mosaic of forest patches and high-altitude grasslands that characterise the site today; however, this influence was tempered by the inaccessibility of the mountain.

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