Replication Of Previous Results Research Articles

A double‐blind sham‐controlled phase 1 clinical trial of tDCS of the dorsolateral prefrontal cortex in cocaine inpatients: Craving, sleepiness, and contemplation to change

Impaired inhibitory control accompanied by enhanced salience attributed to drug-related cues, both associated with function of the dorsolateral prefrontal cortex (dlPFC), are hallmarks of drug addiction, contributing to worse symptomatology including craving. dlPFC modulation with transcranial direct current stimulation (tDCS) previously showed craving reduction in inpatients with cocaine use disorder (CUD). Our study aimed at assessing feasibility of a longer tDCS protocol in CUD (15 versus the common five/10 sessions) and replicability of previous results. In a randomized double-blind sham-controlled protocol, 17 inpatients with CUD were assigned to either a real-tDCS (right anodal/left cathodal) or a sham-tDCS condition for 15 sessions. Following the previous report, primary outcome measures were self-reported craving, anxiety, depression, and quality of life. Secondary measures included sleepiness, readiness to change drug use, and affect. We also assessed cognitive function including impulsivity. An 88% retention rate demonstrated feasibility. Partially supporting the previous results, there was a trend for self-reported craving to decrease in the real-tDCS group more than the sham-group, an effect that would reach significance with 15 subjects per group. Quality of life and impulsivity improved over time in treatment in both groups. Daytime sleepiness and readiness to change drug use showed significant Group×Time interactions whereby improvements were noted only in the real-tDCS group. One-month follow-up suggested transient effects of tDCS on sleepiness and craving. These preliminary results suggest the need for including more subjects to show a unique effect of real-tDCS on craving and examine the duration of this effect. After replication in larger sample sizes, increased vigilance and motivation to change drug use in the real-tDCS group may suggest fortification of dlPFC-supported executive functions.

Last Word Not Yet Spoken: Last Place and Rank Reversal Aversion

Preferences over social ranks have emerged as potential drivers of weaker than expected support for redistributive interventions among those closest to the bottom of the income distribution. We compare preferences for alterations of the income distribution affecting the decision maker's social rank, but not their income, and compare them with similar alterations leaving both rank and income unchanged. We find support for both a discontinuously greater disutility from occupying the last as opposed to higher ranks, thus affecting only those closest to the bottom of the distribution, and for a general dislike of rank reversals affecting most ranks. We moreover contribute to the replication literature by uncovering and correcting a potential reason for the failed replication of previous results. We discuss implications for policy design in both public finance and management science.

The clinical, personality, and genetic correlates of binge drinking: A controlled association study from India

Background and Objectives: Reasonable amount of literature has been accumulated over the years to indicate that the binge drinkers might be different from the group which does not have any history of binging. Only a handful of research demonstrated genetic predisposition for binging. Materials and Methods: This was a clinic-based association study with a case–control design. Two hundred and ten alcohol dependence cases were recruited. Binge drinking was diagnosed using Semi-structured Assessment for Genetics of Alcoholism-II-. Structured instruments were used for the assessment of impulsivity, and novelty seeking traits. single nucleotide polymorphism genotyping was done using Taqmann assay by real-time quantitative polymerase chain reaction (q-PCR) using Taqman assay (ABI 7500) fast real-time PCR system. Results: Comparison of clinical characteristics revealed an earlier age of onset of alcohol use and dependence, significantly more number of accidental injuries, emotional problems, and history of delirium tremens among the binge drinking group. The mean score in the extravagance subscale, overall novelty seeking scale, subscales of nonplanning, and attentional impulsiveness were significantly more among the binge drinkers. With regard to the candidate gene polymorphism (rs25531), short (S) allele of serotonin transporter was observed to be associated with the binge drinking group. Conclusion: Association of impulsiveness and novelty seeking is a new and important finding, indicating the role of personality traits to increase the vulnerability toward binge drinking. The association with the S allele, although is a replication of previous results, is nevertheless important as our study is from a different ethnic population.

Nudging the Paradigm Shift: Everyday Legal Problems in Canada

This paper presents the basic results from the Canadian Forum on Civil Justice Study, Everyday Legal Problems and the Cost of Justice in Canada (2014). The results of the study are similar to previous national legal problems studies carried out in Canada and similarly with the international body of legal problems following the approach taken in Genn’s Paths to Justice research. In addition, the recent Canadian research reports new results on two topics; on the cost of everyday legal problems for both individuals and the state and on the legal capability of Canadians. The replication of previous results and the addition of new data contribute to the access to justice literature and to the discourse surrounding it by nudging the paradigm shift in access to justice away from an exclusive focus on legal problems primary dealt with in the courts to a broader concern with the full range of everyday legal problems experienced by the public.

Towards Youth Happiness and Mental Health in the United Arab Emirates: The Path of Character Strengths in a Multicultural Population

Happiness, good mental health and the possession of character strengths have been proposed in the context of positive psychology as important conditions for achieving a life full of gratification. However, there is a scarcity of studies examining those conditions in Eastern cultural contexts, in order to replicate findings from the Western countries. In this vein, the present study aims to explore the influence of strengths on happiness and mental health in the multicultural context of United Arab Emirates and it is hypothesised that certain strengths are better predictors of happiness and mental health than others, also after controlling for potential sociodemographic confounders. A sample of young university students, in the majority coming from eastern countries was assessed through the Global Happiness Scale, the GHQ-12 and the VIA-IS-120. The results of the regression analyses revealed that the group of character strengths under the denomination of Transcendence together with being young was associated with higher levels of happiness and better mental health. In addition, the possession of strengths of Restraint was associated with less happiness, whilst being a man indicated a better mental health. Such results have important implications regarding the replication of previous results from Western contexts in the context of UAE, highlighting the need for implementation of culturally context-tailored strategies for achieving happiness and mental health through the use of character strengths.

The reliability of continuous brain responses during naturalistic listening to music

Low-level (timbral) and high-level (tonal and rhythmical) musical features during continuous listening to music, studied by functional magnetic resonance imaging (fMRI), have been shown to elicit large-scale responses in cognitive, motor, and limbic brain networks. Using a similar methodological approach and a similar group of participants, we aimed to study the replicability of previous findings. Participants’ fMRI responses during continuous listening of a tango Nuevo piece were correlated voxelwise against the time series of a set of perceptually validated musical features computationally extracted from the music. The replicability of previous results and the present study was assessed by two approaches: (a) correlating the respective activation maps, and (b) computing the overlap of active voxels between datasets at variable levels of ranked significance. Activity elicited by timbral features was better replicable than activity elicited by tonal and rhythmical ones. These results indicate more reliable processing mechanisms for low-level musical features as compared to more high-level features. The processing of such high-level features is probably more sensitive to the state and traits of the listeners, as well as of their background in music.

Chocolate equals stop. Chocolate-specific inhibition training reduces chocolate intake and go associations with chocolate

Earlier research has demonstrated that food-specific inhibition training wherein food cues are repeatedly and consistently mapped onto stop signals decreases food intake and bodyweight. The mechanisms underlying these training effects, however, remain unclear. It has been suggested that consistently pairing stimuli with stop signals induces automatic stop associations with those stimuli, thereby facilitating automatic, bottom-up inhibition. This study examined this hypothesis with respect to food-inhibition training. Participants performed a training that consistently paired chocolate with no go cues (chocolate/no-go) or with go cues (chocolate/go). Following training, we measured automatic associations between chocolate and stop versus go, as well as food intake and desire to eat. As expected, food that was consistently mapped onto stopping was indeed more associated with stopping versus going afterwards. In replication of previous results, participants in the no-go condition also showed less desire to eat and reduced food intake relative to the go condition. Together these findings support the idea that food-specific inhibition training prompts the development of automatic inhibition associations, which subsequently facilitate inhibitory control over unwanted food-related urges.

Replication study of three functional polymorphisms associated with bone mineral density in a cohort of Spanish women

Gene candidate and genome-wide association studies have revealed tens of loci of susceptibility for osteoporosis. Some limitations such as sample size, use of confounding variables, and control for multiple testing and for population stratification, however, represent common problems in these studies that make replication in independent cohorts desirable and even necessary. The main objective of the present study is to replicate previous data on three functional polymorphisms in a cohort of Spanish women. To that end, we performed an association study of three functional polymorphisms previously associated with bone phenotypes in the LRP5, TNFRSF11B, and FGFBP1 genes with low bone mineral density (BMD) in a cohort of 721 Spanish women, most of them postmenopausal. We detected a strong significant association, even when correcting for multiple comparisons, for polymorphism rs312009 in the LRP5 gene with low BMD at the lumbar-spine site. These were women with the CC genotype, which showed the worst bone parameters. Moreover, these women had a higher risk of osteoporosis (adjusted odds ratio 2.82, P = 0.001) than women with the TT/TC genotype. This association seems to be caused because the rs312009 single nucleotide polymorphism (SNP) is located at a binding site for the transcription factor RUNX2 at the 5' region of the LRP5 gene, and the T allele seems to be a better transcriber than the C allele. Regarding the other two SNPs, only the rs4876869 SNP in the TNFRSF11B gene showed a suggestive trend for both skeletal sites. These results underscore the significance of the LRP5 gene in bone metabolism and emphasize the significance of the replication of previous results in independent cohorts.

Still Need for Compelling Evidence to Support the Circadian Dependence of Infarct Size After ST-Elevation Myocardial Infarction

In a Letter to the Editor, Fournier et al1 commented that our statistically nonsignificant results may be because of the use of an overly simple trigonometric transformation (ie, the use of a simple sinus function). We believe that the analysis by Reiter et al2, based on a sinusoid function, is a proper methodology to study the circadian relation of the size of injury after ST-segment–elevation myocardial infarction (STEMI). Considering that the scientific approach is first based on the replication of previous results, we precisely repeated on our data the same analysis that Reiter et al performed (same procedures), but it was unsuccessful. Subsequently, to prove that the lack of regression significance did not depend on the selection of an improper nonlinear function, we also tried several other nonlinear forms that were also unsuccessful (Online Data Supplement).3 In addition, to further assess our results, we decided to test the circadianity using the difference tests (as Fournier et al did in their study), but because the results of the post hoc examination were also nonsignificant, we had to conclude that we did not find a clear-cut circadian dependence of infarct size after STEMI. Fournier et al hypothesized potential differences between our study populations and previous ones that could justify differences in the results. In the Online Tables I and III, we offered characteristics of the first acute …

Temporal stability of the error-related negativity (ERN) and post-error positivity (Pe): The role of number of trials

The error-related negativity (ERN) and post-error positivity (Pe) components of the event-related potential (ERP) are relatively stable over time. The current study further assessed the temporal reliability of ERN and Pe amplitudes for random samples of 2 to 14 trials per participant and the grand mean over a 2-week retest interval. In a replication of previous results, intraclass and zero-order correlations revealed moderate to good temporal stability for participants' (N=20) grand mean ERN and Pe component amplitudes. Adding trials increased test-retest reliabilities; however, the temporal stability of ERN and Pe amplitudes with 14 or fewer trials were modest at best and considerably lower than that for the grand means. Overall, data support the temporal stability of grand-mean ERN and Pe amplitudes and suggest that more than 14 trials are needed to include in ERN and Pe averages for adequate test-retest reliability.

Replicating Results in Archival Publications

Replication of previous results is a basic element in the advancement of science. Traditionally, one of the tenets in publishing research work of archival value is the ability of the reader to replicate the results described in the paper. The implication is that the authors must provide sufficient detail to allow the reader to attempt such replication. Theoretical results can be replicated if the assumptions and basic steps in a proof are properly given. Experimental results can be replicated if the conditions of the experiment are fully described. Computational results can be replicated if sufficient details are given for the computational model (simulation), computing environment, algorithm, and other programming parameters.As the complexity of research work reported has increased, the available publication space (literally, journal pages) has been inadequate for accommodating the amount of detail necessary to allow results replication, as we might have expected it traditionally. In many cases involving computation, it would be unrealistic to expect to have sufficient details or representation in printed form. Thus, in many cases, we trust the authors' reported work, and if we want to replicate it we must contact authors directly, exchange codes or ask further clarifications.In a similar vain, the traditional “test problems” have become increasingly sparse. In many areas, a new idea, theory or algorithm are often demonstrated or tested on relatively simple problems, previously solved by other methods. The advantages of the new approach are then shown in comparison to previous ones, or at least the methods are clarified on a relatively well-known problem. Here again, as our ability to solve complex problems increases, so does the complexity of the test or demonstration problems; and thus our ability to report them sufficiently for replication decreases.An obvious way to address this situation is to take advantage of digital publication, which removes many of the obstacles of space and representation. In January 2008 ASME launched the ASME Digital Library www.asmedl.org as its primary repository of current and archival literature featuring Transaction Journals from 1990 to the present, Conference Proceedings from 2002 to the present, and ASME Press E-Books selected from 1999 to the present. As the ASME Digital Library continues to expand, it ultimately will include the complete archive of ASME's Transactions Journals dating back to 1880. In addition, JMD has for some time now maintained an “alternate” site, to allow posting of upcoming article titles, thus enabling more timely citation of JMD articles soon to appear.In view of the above, I have recently procured the domain name www.asmejmd.org to serve at least two goals: (i) to continue the advanced posting of upcoming publications; and (ii) to provide a venue for authors of JMD articles to post the additional details that would allow replication of results contained in their published article. Professor Matt Parkinson from Penn State University has agreed to perform editorial duties for this new site. We plan this effort as a complement to ASME's Digital Library, and perhaps in the future the materials in question will be incorporated there. For now, the new site will serve as a bona fide archival source of materials that are too extensive or better suited to a digital rather than printed presentation. As we develop the site, I would welcome our readers' and authors' input with respect to its content and function. I would also welcome any other thoughts you may have in addressing the issue of results replication and publication of test problems.

Behavior and the limits of genomic plasticity: power and replicability in microarray analysis of honeybee brains

Transcription is slow relative to many post-transcriptional processes in the brain. Using the rich system of division of labor in the honeybee (Apis mellifera), we found extreme differences in the extent to which behavioral occupations of different durations were associated with gene-expression differences in the brain. Nursing and foraging, occupations lasting > 1 week, were associated with significant expression differences for nearly one-quarter of the genes tested (1208 of 5563 cDNAs tested; P < 0.01, anova), consistent with previous results. In contrast, transitional occupations, performed for 1-2 days after nursing and before the onset of foraging, were associated with either no differences (guards vs. undertakers; 19 cDNAs, fewer than the expectation of 56 false-positives) or few differences (comb builders vs. guards and undertakers; 248 cDNAs), but extensive differences relative to both nursing and foraging (> 500 cDNAs, all contrasts). Statistical power analysis indicated that expression differences of two-, 1.5- and 1.25-fold should have been detected in 100, 92 and 37% of cases, respectively. Replication of previous results at these magnitudes was 95, 71 and 51%, with no genes showing differences in the opposite direction. These results indicate that behavioral plasticity over different time-scales may be associated with substantial differences in the extent of genomic plasticity in the brain.

Reply to Parkinson

Parkinson [1997] cited four criticisms of my reacknowledge the assistance of Parkinson [1995] in bringing this to light. cent paper [Davies, 1996] which I shall here deal with The final criticism concerns statistics. That in in turn. Firstly, I must draw attention to an error within some cases Parkinson arrives at probabilities at differmy paper which although it does not affect the validity ent sides of the P A 0.05 or P A 0.02 thresholds using of the results, may allay one of the criticisms of Parkina t-test rather than a Mann-Whitney test is immaterial son. In Tables 2 and 3 of Davies [1996] a Mann-Whitsince the data are either not normally distributed or not ney U value is indicated where the corresponding statishomoscedastic or both and thus cannot be subjected to tic presented in the Tables is a Mann-Whitney W value. parametric inferential statistics. In any case the probaW is the sum of the ranks of the treatment (E in Tables bility of committing a Type II error is greater with the 2 and 3) values. The probabilities associated with this Mann-Whitney test than with the t-test [e.g., Zar, 1984] statistic remain correct and indicate the probability (usand Parkinson’s adoption of a probability threshold of ing a non-parametric (ranked) test) that the two samples 0.02 is without explanation. The assertion of Parkinson under comparison were drawn from a common populathat parametric statistics are preferable to nonparamettion of values. ric statistics solely on the basis of sample size (in this Parkinson’s first criticism is that the experiment case of n A 13 0 16) is flawed and without reference. is ‘surprisingly’ noisy, although against what the magThat control means are larger than treatment means nitude of the noise is being judged is not clear. Indeed, has no biological relevance when the test statistics indiin two cases within RE1, RE2 and RE3 standard deviacate that the data derived from both treatment and contions are greater than their corresponding means, but trol are likely to be (at PA 0.05 or less) from a common in both cases differences between treatment and control pool. The setting of error rates must be a personal means are not significant. Such variation in biological choice, but I am following convention at 0.05 [e.g., data might be expected and large variances do not Zar, 1984]. disallow statistical comparison. Variance was exThus I contend that it is still clear that, at least pressed as standard error in Davies [1996] in order to on plant height and stem dry weight of radish, the standardise the variance measure to sample size. results presented by Davies [1996] do ‘‘concisely demThe second criticism is that there is large variaonstrate an EMF-effect.’’ tion between experiments. This was acknowledged in Davies [1996], and although temperature was one facREFERENCES tor that differed between the experiments, the origin of Davies MS (1996): Effects of 60 Hz electromagnetic fields on early the variation remains unascribed. It would be naive growth in three plant species and a replication of previous results. to think that all different parameters measured should Bioelectromagnetics 17:154–161. Parkinson WC (1997): Comment on ‘‘Effects of 60 Hz electromagnetic respond in the same way, i.e. all show an increase or fields on early growth in three plant species and a replication decrease, when an experiment is repeated at a different of previous results’’ by Mark S. Davies. Bioelectromagnetics time of year. Similarly it would be naive to equate 18:400. seasonality with temperature. Zar JH (1984): ‘‘Biostatistical Analysis.’’ Englewood Cliffs, New JerThe third criticism I have dealt with above and sey: Prentice-Hall.

Effects of 60 Hz electromagnetic fields on early growth in three plant species and a replication of previous results.

In an attempt to replicate the findings of Smith et al., seeds of Raphanus sativus L. (radish), Sinapsis alba L. (mustard), and Hordeum vulgare L. (barley) were grown for between 9 and 21 days in continuous electromagnetic fields (EMFs) at "ion-cyclotron resonance" conditions for stimulation of Ca(2+) (B(H) = 78.3 mu T, B(HAC) = 40 mu T peak-peak at 60 Hz, B(V) = 0). On harvesting, radish showed results similar to those of Smith et al. Dry stem weight and plant height were both significantly greater (Mann-Whitney tests, Ps < 0.05) in EMF-exposed plants than in control plants in each EMF experiment. Wet root weight was significantly greater in EMF-exposed plants in two out of three experiments, as were dry leaf weight, dry whole weight, and stem diameter. Dry root weight, wet leaf weight, and wet whole weight were significantly greater in EMF-exposed plants in one of three experiments. All significant differences indicated an increase in weight or size in the EMF-exposed plants. In each of the sham experiments, no differences between exposed and control plants were evident. Mustard plants failed to respond to the EMFs in any of the plant parameters measured. In one experiment, barley similarly failed to respond; but in another showed significantly greater wet root weight and significantly smaller stem diameter and dry seed weight at the end of the experiment in exposed plants compared to control plants. Although these results give no clue about the underlying bioelectromagnetic mechanism, they demonstrate that, at least for one EMF-sensitive biosystem, results can be independently replicated in another laboratory. Such replication is crucial in establishing the validity of bioelectromagnetic science.

Interhemispheric learning and speed of hemispheric transmission in dyslexic and normal readers: A replication of previous results and additional findings

ABSTRACTTwo studies evaluated the interhemispheric transmission deficit explanation of reading disability comparing second- and sixth-grade poor and normal readers on learning and discrimination tasks that involved hemifield presentations of visual stimuli. In the first of these studies, in the main poor readers performed below the level of normal readers on paired associates learning, regardless of the visual field in which the stimulus appeared, thereby replicating previous findings. In the second study, no differences between reader groups were found on time taken to indicate presence or absence of a simple dot stimulus. It was concluded from the combined results that deficiency in inter-hemispheric transmission is not a significant cause of reading disability.

Cognitive DissonancevsImpression Management

Abstract Two experiments conducted during academic preregistration tested the competing cognitive dissonance and impression management explanations for the postdecision dissonance phenomenon in the field. In Experiment 1 male and female college students (N = 80) were asked by either a high or a low status male interviewer to evaluate the courses they would be registering for next semester. Half the Ss were asked prior to preregistering, the remaining half after they had preregistered. The results appeared to support cognitive dissonance theory, but questions of interpretation made it necessary to conduct a second experiment (N = 142) using a control condition to determine whether postdecision enhancement or predecision moderation was responsible for the effect. While the findings of the second experiment showed a replication of previous results, further analyses failed to demonstrate that either moderation or enhancement alone could explain the effect, suggesting that both processes may be involved.