scholarly journals Experimental introgression to evaluate the impact of sex specific traits onDrosophila melanogasterincipient speciation

2019 ◽  
Author(s):  
Jérôme Cortot ◽  
Jean-Pierre Farine ◽  
Benjamin Houot ◽  
Claude Everaerts ◽  
Jean-François Ferveur
Keyword(s):  
Sex Pheromones ◽  
Rapid Change ◽  
Sexual Isolation ◽  
Incipient Speciation ◽  
Speciation Process ◽  
Pheromonal Communication ◽  
Highly Correlated ◽  
The Impact ◽  
Overlapping Sets ◽  
Generation Procedure

ABSTRACTSex specific traits are involved in speciation but it is difficult to determine whether their variation initiates or reinforces sexual isolation. In some insects, speciation depends of the rapid change of expression in desaturase genes coding for sex pheromones. Two closely related desaturase genes are involved inDrosophila melanogasterpheromonal communication:desat1affects both the production and the reception of sex pheromones whiledesat2is involved in their production in flies of Zimbabwe populations. There is a strong asymmetric sexual isolation between Zimbabwe populations and all other “Cosmopolitan” populations: Zimbabwe females rarely copulate with Cosmopolitan males whereas Zimbabwe males readily copulate with all females. All populations expressdesat1but only Zimbabwe strains show highdesat2expression. To evaluate the impact of sex pheromones, female receptivity anddesatexpression on the incipient speciation process between Zimbabwe and Cosmopolitan populations, we introgressed the Zimbabwe genome into a Cosmopolitan genome labelled with thewhitemutation, using a multi-generation procedure. The association between these sex-specific traits was determined during the procedure. The production of pheromones was largely dissociated between the sexes. The copulation frequency (but not latency) was highly correlated with the female—but not with the male—principal pheromones. We finally obtained two stablewhitelines showing Zimbabwe-like sex pheromones, copulation discrimination anddesatexpression. Our study indicates that the variation of sex pheromones and of mating discrimination depend of distinct—yet overlapping—sets of genes in each sex suggesting that their cumulated effects participate to reinforce the speciation process.

scholarly journals Music Modulates Cognitive Flexibility? An Investigation of the Benefits of Musical Training on Markers of Cognitive Flexibility

2021 ◽  
Vol 11 (4) ◽  
pp. 451
Author(s):  
Miriam Gade ◽  
Kathrin Schlemmer
Keyword(s):  
Everyday Life ◽  
Cognitive Flexibility ◽  
Musical Training ◽  
Rapid Change ◽  
Task Sequence ◽  
Switch Costs ◽  
Classification Tasks ◽  
Professional Contexts ◽  
The Impact ◽  
Task Sequences

Cognitive flexibility enables the rapid change in goals humans want to attain in everyday life as well as in professional contexts, e.g., as musicians. In the laboratory, cognitive flexibility is usually assessed using the task-switching paradigm. In this paradigm participants are given at least two classification tasks and are asked to switch between them based on valid cues or memorized task sequences. The mechanisms enabling cognitive flexibility are investigated through two empirical markers, namely switch costs and n-2 repetition costs. In this study, we assessed both effects in a pre-instructed task-sequence paradigm. Our aim was to assess the transfer of musical training to non-musical stimuli and tasks. To this end, we collected the data of 49 participants that differed in musical training assessed using the Goldsmiths Musical Sophistication Index. We found switch costs that were not significantly influenced by the degree of musical training. N-2 repetition costs were small for all levels of musical training and not significant. Musical training did not influence performance to a remarkable degree and did not affect markers of mechanisms underlying cognitive flexibility, adding to the discrepancies of findings on the impact of musical training in non-music-specific tasks.

scholarly journals The Influence of Trading Locations on Equity Returns

2016 ◽  
Vol 12 (12) ◽  
pp. 188
Author(s):  
Nguyen N.T. Vo
Keyword(s):  
Risk Premium ◽  
Stock Price ◽  
Listed Companies ◽  
Equity Returns ◽  
Stock Exchanges ◽  
Home Market ◽  
Trade Effect ◽  
Market Index ◽  
Highly Correlated ◽  
The Impact

This paper evaluates the impact of trading locations on equity returns by examining the stock price behaviour of three Anglo-Dutch dual-listed companies which result from mergers where two corporations agree to function as a single operating business, but maintain separate identities. The shares of these stocks are traded not only in their home market but also on several US stock exchanges in the form of American Depository Receipts. Regressing the return differentials on these dual-listed and cross-listed stocks on the relative market index returns and currency changes provides evidence of an apparent violation of the Law of One Price. The regression results show that the return on each part of dual-listed companies is highly correlated with the market on which it is most intensively traded. Similarly, returns on cross-listed stocks have considerably higher co-movement with US market indices and considerably lower co-movement with home-market indices than their home-market counterparts. Market risk premium is not a significant explanatory variable of the location of trade effect.

Asymptotically matched sheath and presheath in a dense plasma

1998 ◽  
Vol 59 (3) ◽  
pp. 505-536 ◽  
Author(s):  
LINDSEY D. THORNHILL ◽  
PRATEEN V. DESAI
Keyword(s):  
Rapid Change ◽  
Debye Length ◽  
Mean Free Path ◽  
Boundary Region ◽  
Surface Erosion ◽  
Leading Order ◽  
Power Flux ◽  
Temperature Plasma ◽  
Recombination Length ◽  
The Impact

Asymptotically matched solutions for electron and ion density, electron and ion velocity, and electric potential are obtained in the boundary region of a dense low-temperature plasma adjacent to perfectly absorbing walls – walls that absorb, without reflection, incident electrons and ions. Leading-order composite solutions, valid throughout the boundary region, are constructed from solutions in three subdomains distinguished by different physical length scales: the geometric length, the ion mean free path and the Debye length. The composite solutions are used to assess the impact of electron–ion recombination in the ionization nonequilibrium region on sheath and presheath profiles, and on quantities evaluated at the wall. While, at leading order, the velocity profiles throughout the boundary region are not influenced by recombination, the density and potential profiles are significantly altered when recombination is included. These results show that the region of rapid change in these profiles lies closer to the wall when recombination is explicitly included in the model. The influence of recombination on the presheath potential, and consequently the wall potential, is found to scale as the natural logarithm of the recombination length. The broadening of the density profile results in a larger flux of ions accelerating through the sheath and impacting on the wall. The influence of recombination on the ion power flux to the wall is found to scale with the inverse recombination length. This scaling influences the prediction of surface erosion rates in technological applications that utilize these plasmas.

scholarly journals Exploiting correlated molecular-dynamics networks to counteract enzyme activity–stability trade-off

2018 ◽  
Vol 115 (52) ◽  
pp. E12192-E12200 ◽  
Author(s):  
Haoran Yu ◽  
Paul A. Dalby
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Active Site ◽  
Dynamic Networks ◽  
Aromatic Aldehydes ◽  
Active Site Residues ◽  
Trade Off ◽  
Highly Correlated ◽  
Dynamics Simulations ◽  
The Impact

The directed evolution of enzymes for improved activity or substrate specificity commonly leads to a trade-off in stability. We have identified an activity–stability trade-off and a loss in unfolding cooperativity for a variant (3M) of Escherichia coli transketolase (TK) engineered to accept aromatic substrates. Molecular dynamics simulations of 3M revealed increased flexibility in several interconnected active-site regions that also form part of the dimer interface. Mutating the newly flexible active-site residues to regain stability risked losing the new activity. We hypothesized that stabilizing mutations could be targeted to residues outside of the active site, whose dynamics were correlated with the newly flexible active-site residues. We previously stabilized WT TK by targeting mutations to highly flexible regions. These regions were much less flexible in 3M and would not have been selected a priori as targets using the same strategy based on flexibility alone. However, their dynamics were highly correlated with the newly flexible active-site regions of 3M. Introducing the previous mutations into 3M reestablished the WT level of stability and unfolding cooperativity, giving a 10.8-fold improved half-life at 55 °C, and increased midpoint and aggregation onset temperatures by 3 °C and 4.3 °C, respectively. Even the activity toward aromatic aldehydes increased up to threefold. Molecular dynamics simulations confirmed that the mutations rigidified the active-site via the correlated network. This work provides insights into the impact of rigidifying mutations within highly correlated dynamic networks that could also be useful for developing improved computational protein engineering strategies.

scholarly journals The Impact of Criteria-based and Data-driven Sampling Approaches on the Heterogeneity and Interpretability of Posttraumatic Stress Symptom Networks

2020 ◽  
Author(s):  
Santiago Papini ◽  
Mikael Rubin ◽  
Michael J Telch ◽  
Jasper A. J. Smits
Keyword(s):  
Data Driven ◽  
Network Heterogeneity ◽  
Psychopathological Symptom ◽  
Highly Correlated ◽  
And Cluster Analysis ◽  
Sensitivity Specificity ◽  
Future Work ◽  
The Impact ◽  
Sample Heterogeneity ◽  
Source Of Error

Background. The application of psychopathological symptom networks requires reconciliation of the observed cross-sample heterogeneity. We leveraged the largest sample to be used in a PTSD network analysis (N = 28,594) to examine the impact of criteria-based and data-driven sampling approaches on the heterogeneity and interpretability of networks.Methods. Severity and diagnostic criteria identified four overlapping subsamples and cluster analysis identified three distinct data-derived profiles. Networks estimated on each subsample were compared to a respective benchmark network at the symptom-relation level by calculating sensitivity, specificity, correlation, and density of the edges. Negative edges were assessed for Berkson’s bias, a source of error that can be induced by threshold samples on severity.Results. Criteria-based networks showed reduced sensitivity, specificity, and density but edges remained highly correlated and a meaningfully higher proportion of negative edges was not observed relative to the benchmark network of all cases. Among the data-derived profile networks, the Low Severity network had the highest proportion of negative edges not present in the benchmark network of symptomatic cases. The High Severity profile also showed a higher proportion of negative edges, whereas the Medium Severity profile did not. Conclusion. Although networks showed differences, Berkson’s bias did not appear to be a meaningful source of systematic error. These results can guide expectations about the generalizability of symptom networks across samples that vary in their ranges of severity. Future work should continue to explore whether network heterogeneity is reflective of meaningful and interpretable differences in the symptom relations from which they are composed.

scholarly journals Spontaneous HTLV-1 transcription is accompanied by distinct epigenetic changes in the 5′ and 3′ long terminal repeats

2018 ◽  
Vol 3 ◽  
pp. 105 ◽  
Author(s):  
Michi Miura ◽  
Paola Miyazato ◽  
Yorifumi Satou ◽  
Yuetsu Tanaka ◽  
Charles R.M. Bangham
Keyword(s):  
Histone Modifications ◽  
Insertion Site ◽  
Rapid Change ◽  
Epigenetic Modifications ◽  
The Body ◽  
Ctcf Binding ◽  
Ctcf Binding Site ◽  
Long Terminal Repeats ◽  
Terminal Repeats ◽  
The Impact

Background:The human retrovirus HTLV-1 inserts the viral complementary DNA of 9 kb into the host genome. Both plus- and minus-strands of the provirus are transcribed, respectively from the 5′ and 3′ long terminal repeats (LTR). Plus-strand expression is rapid and intense once activated, whereas the minus-strand is transcribed at a lower, more constant level. To identify how HTLV-1 transcription is regulated, we investigated the epigenetic modifications associated with the onset of spontaneous plus-strand expression and the potential impact of the host factor CTCF.Methods:Patient-derived peripheral blood mononuclear cells (PBMCs) and in vitro HTLV-1-infected T cell clones were examined. Cells were stained for the plus-strand-encoded viral protein Tax, and sorted into Tax+and Tax–populations. Chromatin immunoprecipitation and methylated DNA immunoprecipitation were performed to identify epigenetic modifications in the provirus. Bisulfite-treated DNA fragments from the HTLV-1 LTRs were sequenced. Single-molecule RNA-FISH was performed, targeting HTLV-1 transcripts, for the estimation of transcription kinetics. The CRISPR/Cas9 technique was applied to alter the CTCF-binding site in the provirus, to test the impact of CTCF on the epigenetic modifications.Results:Changes in the histone modifications H3K4me3, H3K9Ac and H3K27Ac were strongly correlated with plus-strand expression. DNA in the body of the provirus was largely methylated except for the pX and 3′ LTR regions, regardless of Tax expression. The plus-strand promoter was hypomethylated when Tax was expressed. Removal of CTCF had no discernible impact on the viral transcription or epigenetic modifications.Conclusions:The histone modifications H3K4me3, H3K9Ac and H3K27Ac are highly dynamic in the HTLV-1 provirus: they show rapid change with the onset of Tax expression, and are reversible. The HTLV-1 provirus has an intrinsic pattern of epigenetic modifications that is independent of both the provirus insertion site and the chromatin architectural protein CTCF which binds to the HTLV-1 provirus.

scholarly journals Re-thinking Public Health Education in Aotearoa New Zealand: Factory Model to Personalized Learning

2021 ◽  
Vol 6 ◽  
Author(s):  
Cath Conn ◽  
Shoba Nayar ◽  
Margaret Hinepo Williams ◽  
Radilaite Cammock
Keyword(s):  
Public Health ◽  
Rapid Change ◽  
Public Health Education ◽  
Personalized Learning ◽  
Project Based Learning ◽  
Public Health Workforce ◽  
Fostering Creativity ◽  
Educational Paradigm ◽  
Societal Expectations ◽  
The Impact

Key drivers of change in the 21st century—pandemic, technology advance, social disparity—are shaping the public health industry, including employment and education. In 2020, COVID-19 brought rapid change to the teaching of public health in higher education. In this reflective essay, we move beyond the delivery of existing curricula shifting from classroom to online, and consider the greater agenda of a transformative educational paradigm. This is broadly conceptualized as a shift from a “factory model education” to one of “personalized learning” with an emphasis on fostering creativity and heutagogical (student-driven) models, underpinned by technology, and real world application involving problem and project-based learning in a changing industry. Such change has stemmed both from the impact of COVID-19 on the education system, and in response to a more momentous transformation in public health careers and societal expectations of a public health workforce.

scholarly journals Dynamics of Gender-Specific Behaviors in the Digital Educational Environment

2021 ◽  
Vol 15 (24) ◽  
pp. 155-166
Author(s):  
Jeļena Badjanova ◽  
Dzintra Iliško ◽  
Svetlana Ignatjeva ◽  
Margarita Nesterova
Keyword(s):  
Information And Communication Technologies ◽  
Rapid Change ◽  
Female Gender ◽  
Well Being ◽  
Educational Environment ◽  
Digital Learning ◽  
And Gender ◽  
Teachers Professional Development ◽  
The Impact ◽  
Gender Specific

During the social distancing, an increasing number of people use communication applications, various types of digital tools and programs. Various video conferencing platforms are regularly used in the educational environment. The study presents the analyses how intensive is the use of Information and Communication Technologies (ICT) in the educational environment and how it can change cognitive-behavioral gender differences. This is particularly important to pay a special attention to the analysis of gender as a dynamic category, to take into account the processes of gender socialization and transformation of gender identification in the changing social environment. The research methods also included a set of additional methods, such as a focus group on different aspects of gender-specific behavior in the digital learning environment, putting together collages, as well as the method of the unfinished sentence related to the impact of ICT on teachers' professional development and well-being. In the course of the study, it was recognised that the design of social models of male and female gender-specific behaviour includes more than the basic gender identity and gender stability: in today's society, there is a multiplicity of views on the similarities and differences of gender-specific behaviours, and a rapid change in the accepted social guidelines and behavioural patterns is in progress, socio-cultural norms that define the psychological characteristics of women and men, their patterns of behaviour.

scholarly journals Edaphic characteristics of Austrian pine (Pinus nigra Arn.) forests in the Visegrad area

2016 ◽  
Vol 68 (2) ◽  
pp. 355-362
Author(s):  
Velibor Blagojevic ◽  
Milan Knezevic ◽  
Olivera Kosanin ◽  
Marijana Kapovic-Solomun ◽  
Radovan Lucic ◽  
...  
Keyword(s):  
Pinus Nigra ◽  
Research Area ◽  
Geological Structure ◽  
Forest Communities ◽  
Production Potential ◽  
High Production ◽  
Highly Correlated ◽  
The Impact ◽  
Important Basis ◽  
Forest Habitats

This paper presents the results of soil research in Austrian pine (Pinus nigra Arn.) forest communities in the Visegrad area, carried out to determine the basic soil characteristics and eco-production potential of forest habitats as an important basis and framework for the successful management of these forests on the principles of sustainable development. Austrian pine forests in this region are an important and ecologically valuable community. The complexity of the geological structure and relief dynamics are dominant environmental factors that condition the expressed variability of soils in the study area. Forest communities of Austrian pine are formed on the peridotites and serpentinites, eutric ranker (haplic leptosol), eutric cambisol (haplic cambisols) and pseudogley (haplic planosol), dense granular and marl limestones calcomelanosol (mollic leptosol), rendzina (rendzic leptosol) and calcocambisol (leptic cambisol). The productivity of these soils is highly correlated with depth and texture composition, and the impact of these factors is linked with soil type, climate and other site conditions. In the research area, soil types with low production potential such as rankers, rendzinas, limestone and dolomite calcomelanosol are dominant. Deeper variants of eutric cambisol, pseudogley and calcocambisol can be classified as soils with moderate to high production potential.

scholarly journals Measuring impacts of an holistic farm business management training program

2004 ◽  
Vol 44 (6) ◽  
pp. 531 ◽  
Author(s):  
D. Cameron ◽  
S. A. Chamala
Keyword(s):  
Formal Education ◽  
Business Management ◽  
Management Training ◽  
Self Directed Learning ◽  
Study Approach ◽  
Management Objectives ◽  
Directed Learning ◽  
Highly Correlated ◽  
Farm Business ◽  
The Impact

A case study approach within an action research framework incorporating qualitative and quantitative domains was adopted to explore the impact on Queensland farmers of a farm business management extension programme. Three new indices were developed to quantify changes perceived by participants. The first measure, the Bennett Change Index, provided statistically significant evidence that attitudinal and behavioural changes were more frequent in participants with less formal education, but also more frequent in participants who had high urbanisation and self-directed learning index scores. The other 2 new indices, Management Constructs Change and Management Objectives Change, provided evidence of statistically significant changes in participant beliefs about, and attitudes towards, farm business management. Although highly correlated with each other, these changes were unrelated statistically to any of 6 other commonly used biographical or psychometric indices employed; including level of formal education. It is concluded that these new measures, with context-relevant modifications, have potential as aids to programme impact evaluation in a range of agricultural and wider applications. They may provide insights into personal psychological issues that complement direct behavioural measures of change.

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