scholarly journals Causes of variability in estimates of mutational variance from mutation accumulation experiments

2021 ◽  
Author(s):  
Cara Conradsen ◽  
Mark W. Blows ◽  
Katrina McGuigan
Keyword(s):  
Repeated Measures ◽  
Sampling Error ◽  
Natural Populations ◽  
Mutation Accumulation ◽  
Short Term ◽  
Experimental Conditions ◽  
Drosophila Serrata ◽  
Vinegar Fly ◽  
Low Levels ◽  
Mutational Variance

Characteristics of the new phenotypic variation introduced via mutation have broad implications in evolutionary and medical genetics. While many estimates of this mutational variance have been published, factors contributing to their range, spanning two orders of magnitude, remain poorly resolved. In this study, we first apply a meta-analytic approach to assess how previously implicated factors affect variability in estimates. While estimates of mutational variance are available from a range of taxa, and quantitative trait type over a range of timescales, these factors are confounded with one another, precluding a clear resolution of causes of observed variability. We call for further directly comparable empirical data to address this question. We then applied a modified mutation accumulation experimental design to generate independent repeated estimates of mutational variance for a single taxon (the vinegar fly, Drosophila serrata), and for a single trait type (wing morphology) under the same experimental conditions. Analyses revealed that, in this tightly controlled experiment, variability in among-line (mutational) variance was largely the consequence of sampling error. Micro-environmental variation in mutational effects was supported as a cause of low levels of variability in mutational variance for two of 11 traits analysed. Further, there was no evidence that variation in segregating mutations, as the realisation of the mutation-drift process, impacted estimates. This investigation demonstrates the utility of short-term repeated measures to be broadly applied to improve estimates of mutational variance, consequently expanding our understanding of the dynamics of mutations in natural populations.

Use of spectral analysis to estimate short-term periodicities in growth rates of brook trout Salvelinus frontinalis

1997 ◽  
Vol 54 (7) ◽  
pp. 1532-1541 ◽  
Author(s):  
W Aboul Hosn ◽  
P Dutilleul ◽  
D Boisclair
Keyword(s):  
Growth Rate ◽  
Spectral Analysis ◽  
Growth Rates ◽  
Repeated Measures ◽  
Brook Trout ◽  
Short Term ◽  
Experimental Conditions ◽  
Relative Growth Rates ◽  
Repeated Measures Design ◽  
Periodic Components

We used spectral analysis to investigate the periodic components of relative growth rates (on a mass and length basis) in two groups of six\b young-of-the-year brook trout (Salvelinus fontinalis). Fish were measured every 2 days for 25 days according to a repeated measures design in time. The predominant frequency components were estimated at the end of a stepwise procedure involving the analysis of the multifrequential periodogram. We found mainly two superimposed periodic components that resulted in short rhythms; these had a period of about 5 and 10 days for the growth rate in mass and of about 4 and 6 days for the growth rate in length (R2 = 91% for mass and 90% for length, both including an autocorrelation term). Repeatability of rhythms was assessed by ANOVA of the finite Fourier transform, which showed that the two groups of fish reared under the same experimental conditions exhibited growth rhythms that were not significantly different from each other. On that basis, we present a harmonic model which predicts short-term variation in growth rate of brook trout in mass (R2pred = 0.73, with an autocorrelation term) and in length (R2pred = 0.72).

Evaluation of Acoustic Analyses of Voice in Nonoptimized Conditions

2020 ◽  
Vol 63 (12) ◽  
pp. 3991-3999
Author(s):  
Benjamin van der Woerd ◽  
Min Wu ◽  
Vijay Parsa ◽  
Philip C. Doyle ◽  
Kevin Fung
Keyword(s):  
Repeated Measures ◽  
Voice Quality ◽  
Data Sets ◽  
Acoustic Measurements ◽  
Sample Collection ◽  
Experimental Conditions ◽  
Environment Analysis ◽  
Acoustic Measures ◽  
Recording Conditions ◽  
Cepstral Peak Prominence

Objectives This study aimed to evaluate the fidelity and accuracy of a smartphone microphone and recording environment on acoustic measurements of voice. Method A prospective cohort proof-of-concept study. Two sets of prerecorded samples (a) sustained vowels (/a/) and (b) Rainbow Passage sentence were played for recording via the internal iPhone microphone and the Blue Yeti USB microphone in two recording environments: a sound-treated booth and quiet office setting. Recordings were presented using a calibrated mannequin speaker with a fixed signal intensity (69 dBA), at a fixed distance (15 in.). Each set of recordings (iPhone—audio booth, Blue Yeti—audio booth, iPhone—office, and Blue Yeti—office), was time-windowed to ensure the same signal was evaluated for each condition. Acoustic measures of voice including fundamental frequency ( f o ), jitter, shimmer, harmonic-to-noise ratio (HNR), and cepstral peak prominence (CPP), were generated using a widely used analysis program (Praat Version 6.0.50). The data gathered were compared using a repeated measures analysis of variance. Two separate data sets were used. The set of vowel samples included both pathologic ( n = 10) and normal ( n = 10), male ( n = 5) and female ( n = 15) speakers. The set of sentence stimuli ranged in perceived voice quality from normal to severely disordered with an equal number of male ( n = 12) and female ( n = 12) speakers evaluated. Results The vowel analyses indicated that the jitter, shimmer, HNR, and CPP were significantly different based on microphone choice and shimmer, HNR, and CPP were significantly different based on the recording environment. Analysis of sentences revealed a statistically significant impact of recording environment and microphone type on HNR and CPP. While statistically significant, the differences across the experimental conditions for a subset of the acoustic measures (viz., jitter and CPP) have shown differences that fell within their respective normative ranges. Conclusions Both microphone and recording setting resulted in significant differences across several acoustic measurements. However, a subset of the acoustic measures that were statistically significant across the recording conditions showed small overall differences that are unlikely to have clinical significance in interpretation. For these acoustic measures, the present data suggest that, although a sound-treated setting is ideal for voice sample collection, a smartphone microphone can capture acceptable recordings for acoustic signal analysis.

scholarly journals Accuracy of emergency physicians’ self-estimates of CT scan utilization and its potential effect on an audit and feedback intervention: a randomized trial

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Celine Larkin ◽  
Alexandra M. Sanseverino ◽  
James Joseph ◽  
Lauren Eisenhauer ◽  
Martin A. Reznek
Keyword(s):  
Randomized Trial ◽  
Repeated Measures ◽  
Intervention Group ◽  
Potential Effect ◽  
Audit And Feedback ◽  
Emergency Physicians ◽  
Feedback Intervention ◽  
Experimental Conditions ◽  
Actual Performance ◽  
Ct Utilization

Abstract Background Audit and feedback (A&F) has been used as a strategy to modify clinician behavior with moderate success. Although A&F is theorized to work by improving the accuracy of clinicians’ estimates of their own behavior, few interventions have included assessment of clinicians’ estimates at baseline to examine whether they account for intervention success or failure. We tested an A&F intervention to reduce computed tomography (CT) ordering by emergency physicians, while also examining the physicians’ baseline estimates of their own behavior compared to peers. Methods Our study was a prospective, multi-site, 20-month, randomized trial to examine the effect of an A&F intervention on CT ordering rates, overall and by test subtype. From the electronic health record, we obtained 12 months of baseline CT ordering per 100 patients treated for every physician from four emergency departments. Those who were randomized to receive A&F were shown a de-identified graph of the group’s baseline CT utilization, asked to estimate wherein the distribution of their own CT order practices fell, and then shown their actual performance. All participants also received a brief educational intervention. CT ordering rates were collected for all physicians for 6 months after the intervention. Pre-post ordering rates were compared using independent and repeated measures t tests. Results Fifty-one of 52 eligible physicians participated. The mean CT ordering rate increased significantly in both experimental conditions after the intervention (intervention pre = 35.7, post = 40.3, t = 4.13, p < 0.001; control pre = 33.9, post = 38.9, t = 3.94, p = 0.001), with no significant between-group difference observed at follow-up (t = 0.43, p = 0.67). Within the intervention group, physicians had poor accuracy in estimating their own ordering behavior at baseline: most overestimated and all guessed that they were in the upper half of the distribution of their peers. CT ordering increased regardless of self-estimate accuracy. Conclusions Our A&F intervention failed to reduce physician CT ordering: our feedback to the physicians showed most of them that they had overestimated their CT ordering behavior, and they were therefore unlikely to reduce it as a result. After “audit,” it may be prudent to assess baseline clinician awareness of behavior before moving toward a feedback intervention.

scholarly journals On the Rate and Linearity of Viability Declines in Drosophila Mutation-Accumulation Experiments: Genomic Mutation Rates and Synergistic Epistasis Revisited

Genetics ◽  
2004 ◽  
Vol 166 (2) ◽  
pp. 797-806 ◽  
Author(s):  
James D Fry
Keyword(s):  
Mutation Rate ◽  
Average Rate ◽  
Natural Populations ◽  
Mutation Accumulation ◽  
High Rate ◽  
Deleterious Mutations ◽  
Order Of Magnitude ◽  
Contamination Event ◽  
Genomic Mutation ◽  
The 1960S

Abstract High rates of deleterious mutations could severely reduce the fitness of populations, even endangering their persistence; these effects would be mitigated if mutations synergize each others’ effects. An experiment by Mukai in the 1960s gave evidence that in Drosophila melanogaster, viability-depressing mutations occur at the surprisingly high rate of around one per zygote and that the mutations interact synergistically. A later experiment by Ohnishi seemed to support the high mutation rate, but gave no evidence for synergistic epistasis. Both of these studies, however, were flawed by the lack of suitable controls for assessing viability declines of the mutation-accumulation (MA) lines. By comparing homozygous viability of the MA lines to simultaneously estimated heterozygous viability and using estimates of the dominance of mutations in the experiments, I estimate the viability declines relative to an appropriate control. This approach yields two unexpected conclusions. First, in Ohnishi’s experiment as well as in Mukai’s, MA lines showed faster-than-linear declines in viability, indicative of synergistic epistasis. Second, while Mukai’s estimate of the genomic mutation rate is supported, that from Ohnishi’s experiment is an order of magnitude lower. The different results of the experiments most likely resulted from differences in the starting genotypes; even within Mukai’s experiment, a subset of MA lines, which I argue probably resulted from a contamination event, showed much slower viability declines than did the majority of lines. Because different genotypes may show very different mutational behavior, only studies using many founding genotypes can determine the average rate and distribution of effects of mutations relevant to natural populations.

Objective assessment of nasal resistance among electronic cigarette users

2021 ◽  
pp. 1-4
Author(s):  
S W Lim ◽  
AB Zulkiflee
Keyword(s):  
Tobacco Smoking ◽  
Repeated Measures ◽  
Airway Resistance ◽  
Electronic Cigarettes ◽  
Objective Assessment ◽  
Control Group ◽  
Nasal Airway ◽  
Nasal Resistance ◽  
Short Term ◽  
Nasal Airway Resistance

Abstract Background Electronic cigarettes have been a popular alternative to tobacco smoking. The effect of tobacco smoking on nasal airway resistance has been investigated before; however, the effect of the aerosol generated by electronic cigarettes is still unknown. This study aimed to evaluate the short-term effects of e-cigarettes on nasal airway resistance. Methods Sixty-one participants were recruited into a vapers group and a control group. The vapers group was instructed to smoke for 5 minutes, and their nasal resistance was measured pre-procedure and at 1 and 5 minutes post-procedure. The results were compared between both groups. Results Repeated measures analysis of variance demonstrated that vaping has no statistically significant effect on total nasal airway resistance. Conclusion Although the differences between both groups were not statistically significant overall, the vapers group showed a reduction in nasal airway resistance in the short term.

scholarly journals Gut Microbiota Dynamics in Natural Populations of Pintomyia evansi under Experimental Infection with Leishmania infantum

2021 ◽  
Vol 9 (6) ◽  
pp. 1214
Author(s):  
Rafael José Vivero ◽  
Victor Alfonso Castañeda-Monsalve ◽  
Luis Roberto Romero ◽  
Gregory D. Hurst ◽  
Gloria Cadavid-Restrepo ◽  
...  
Keyword(s):  
Gut Microbiota ◽  
Leishmania Infantum ◽  
Natural Populations ◽  
Illumina Miseq ◽  
Urban Environments ◽  
High Load ◽  
Leishmania Infection ◽  
Experimental Conditions ◽  
Rural And Urban ◽  
Negative Effect

Pintomyia evansi is recognized by its vectorial competence in the transmission of parasites that cause fatal visceral leishmaniasis in rural and urban environments of the Caribbean coast of Colombia. The effect on and the variation of the gut microbiota in female P. evansi infected with Leishmania infantum were evaluated under experimental conditions using 16S rRNA Illumina MiSeq sequencing. In the coinfection assay with L. infantum, 96.8% of the midgut microbial population was composed mainly of Proteobacteria (71.0%), followed by Cyanobacteria (20.4%), Actinobacteria (2.7%), and Firmicutes (2.7%). In insect controls (uninfected with L. infantum) that were treated or not with antibiotics, Ralstonia was reported to have high relative abundance (55.1–64.8%), in contrast to guts with a high load of infection from L. infantum (23.4–35.9%). ASVs that moderately increased in guts infected with Leishmania were Bacillus and Aeromonas. Kruskal–Wallis nonparametric variance statistical inference showed statistically significant intergroup differences in the guts of P. evansi infected and uninfected with L. infantum (p < 0.05), suggesting that some individuals of the microbiota could induce or restrict Leishmania infection. This assay also showed a negative effect of the antibiotic treatment and L. infantum infection on the gut microbiota diversity. Endosymbionts, such as Microsporidia infections (<2%), were more often associated with guts without Leishmania infection, whereas Arsenophonus was only found in guts with a high load of Leishmania infection and treated with antibiotics. Finally, this is the first report that showed the potential role of intestinal microbiota in natural populations of P. evansi in susceptibility to L. infantum infection.

scholarly journals ‘It isn't my area.’ Coaches’ awareness of concussion protocols in Scottish youth football

2021 ◽  
Vol 30 (1) ◽  
pp. 53-73
Author(s):  
David McArdle ◽  
Anne DeMartini ◽  
Sungwon Kim ◽  
Daniel Connaughton
Keyword(s):  
Short Term ◽  
Apparent Lack ◽  
Sports Concussion ◽  
Youth Football ◽  
Funded Project ◽  
Low Levels

This paper discusses an externally-funded project into Scottish coaches’ awareness of the sports concussion prevention initiative, If in Doubt, Sit Them Out. It explores the short-term risks of concussion to youth participants in particular before analysing the data from interviews with ten coaches of girls’ football. The coaches’ apparent lack of awareness of the policy are highlighted and the possibility that the different resources in girls’ and boys’ football, and between girls’ performance and girls’ recreational participation, might impact on injury recognition and treatment, are explored. The paper highlights the need for further research into those areas, and the need to immediately address the apparently low levels of awareness of If in Doubt. With that in mind, proposals for both immediate and longer-term reform for its dissemination are introduced.

scholarly journals Effect of Carnatic Music Listening Training on Speech in Noise Performance in Adults

2021 ◽  
Vol 25 (1) ◽  
pp. 22-26
Author(s):  
Raksha Amemane ◽  
Archana Gundmi ◽  
Kishan Madikeri Mohan
Keyword(s):  
Repeated Measures ◽  
Functional Organization ◽  
Control Group ◽  
Music Listening ◽  
Noise Performance ◽  
Short Term ◽  
Speech In Noise ◽  
Carnatic Music ◽  
Significant Difference ◽  
And Control

Background and Objectives: Music listening has a concomitant effect on structural and functional organization of the brain. It helps in relaxation, mind training and neural strengthening. In relation to it, the present study was aimed to find the effect of Carnatic music listening training (MLT) on speech in noise performance in adults.Subjects and Methods: A total of 28 participants (40-70 years) were recruited in the study. Based on randomized control trial, they were divided into intervention and control group. Intervention group underwent a short-term MLT. Quick Speech-in-Noise in Kannada was used as an outcome measure.Results: Results were analysed using mixed method analysis of variance (ANOVA) and repeated measures ANOVA. There was a significant difference between intervention and control group post MLT. The results of the second continuum revealed no statistically significant difference between post training and follow-up scores in both the groups.Conclusions: In conclusion short-term MLT resulted in betterment of speech in noise performance. MLT can be hence used as a viable tool in formal auditory training for better prognosis.

scholarly journals Mechanisms behind the portion size effect-visibility and bite size

2017 ◽  
Author(s):  
Kyle Stanley Burger ◽  
Susan L. Johnson
Keyword(s):  
Size Effect ◽  
Energy Intake ◽  
Repeated Measures ◽  
Visual Cues ◽  
Normal Weight ◽  
Portion Size ◽  
Experimental Conditions ◽  
Bite Size ◽  
Subject Design ◽  
Participant Characteristics

Increases in portion size lead to increases in energy intake, yet the mechanisms behind this ‘portion size effect’ are unclear. This study tested possible mechanisms of the portion size effect i.e., bite size and visual cues in 30 over- and normal-weight individuals (15 men, 15 women). A 2x2 repeated measures, within-subject design was used to test the effects of portion size (410g vs. 820g of a pasta dish) and visual cues (blindfolded vs. visible) on energy intake. At each meal participants were exposed to one of four experimental conditions (small portion/visible; small portion/blindfold; large portion/visible; large portion/blindfold). Participant characteristics, food intake, number of bites, meal duration, palatability measures and hunger and fullness were assessed. In response to a doubling of the portion presented, entrée energy intake increased 26% (220kcal P &lt; 0.001) and mean bite size increased 2.4g/bite (P &lt; 0.05). Overweight individuals consumed 40% (334kcal) more of the entrée in response to the large portion condition (P &lt; 0.05), while lean individuals’ intakes did not differ (P &lt; 0.56). A 12% (122kcal) decrease in entrée intake was observed in the blindfolded condition (P &lt; 0.01), but no portion by visual cue interaction was found; indicating that blindfolding did not attenuate the portion size effect. These data suggest that the portion size effect is greater in overweight individuals and occurs via changes in bite size.

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