scholarly journals Chemical patterns of colony membership and mother-offspring similarity in Antarctic fur seals are reproducible over time

2020 ◽  
Author(s):  
Jonas Tebbe ◽  
Emily Humble ◽  
Martin A. Stoffel ◽  
Lisa J. Tewes ◽  
Caroline Müller ◽  
...  
Keyword(s):  
Statistical Power ◽  
Small Sample ◽  
Chemical Data ◽  
Gas Chromatography Mass Spectrometry ◽  
Original Research ◽  
Replication Studies ◽  
Fur Seals ◽  
Research Findings ◽  
Over Time ◽  
Antarctic Fur Seals

AbstractReplication studies are essential for assessing the validity of previous research findings and for probing their generality. However, it has proven challenging to reproduce the results of ecological and evolutionary studies, partly because of the complexity and lability of many of the phenomena being investigated, but also due to small sample sizes, low statistical power and publication bias. Additionally, replication is often considered too difficult in field settings where many factors are beyond the investigator’s control and where spatial and temporal dependencies may be strong. We investigated the feasibility of reproducing original research findings in the field of chemical ecology by attempting to replicate a previous study by our team on Antarctic fur seals (Arctocephalus gazella). In the original study, skin swabs from 41 mother-offspring pairs from two adjacent breeding colonies on Bird Island, South Georgia, were analysed using gas chromatography-mass spectrometry. Seals from the two colonies differed significantly in their chemical fingerprints, suggesting that colony membership may be chemically encoded, and mothers were also chemically similar to their pups, implying that phenotype matching may be involved in mother-offspring recognition. Here, we generated and analysed comparable chemical data from a non-overlapping sample of 50 mother-offspring pairs from the same two colonies five years later. The original results were corroborated in both hypothesis testing and estimation contexts, with p-values remaining highly significant and effect sizes, standardized between studies by bootstrapping the chemical data over individuals, being of comparable magnitude. We furthermore expanded the geographic coverage of our study to include pups from a total of six colonies around Bird Island. Significant chemical differences were observed in the majority of pairwise comparisons, indicating not only that patterns of colony membership persist over time, but also that chemical signatures are colony-specific in general. Our study systematically confirms and extends our previous findings, while also implying that temporal and spatial heterogeneity need not necessarily negate the reproduction and generalization of ecological research findings.

scholarly journals Chemical patterns of colony membership and mother-offspring similarity in Antarctic fur seals are reproducible

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10131
Author(s):  
Jonas Tebbe ◽  
Emily Humble ◽  
Martin Adam Stoffel ◽  
Lisa Johanna Tewes ◽  
Caroline Müller ◽  
...  
Keyword(s):  
Statistical Power ◽  
Small Sample ◽  
Chemical Data ◽  
Gas Chromatography Mass Spectrometry ◽  
Original Research ◽  
Replication Studies ◽  
Fur Seals ◽  
Research Findings ◽  
Antarctic Fur Seals ◽  
Exact Replication

Replication studies are essential for evaluating the validity of previous research findings. However, it has proven challenging to reproduce the results of ecological and evolutionary studies, partly because of the complexity and lability of many of the phenomena being investigated, but also due to small sample sizes, low statistical power and publication bias. Additionally, replication is often considered too difficult in field settings where many factors are beyond the investigator’s control and where spatial and temporal dependencies may be strong. We investigated the feasibility of reproducing original research findings in the field of chemical ecology by performing an exact replication of a previous study of Antarctic fur seals (Arctocephalus gazella). In the original study, skin swabs from 41 mother-offspring pairs from two adjacent breeding colonies on Bird Island, South Georgia, were analyzed using gas chromatography-mass spectrometry. Seals from the two colonies differed significantly in their chemical fingerprints, suggesting that colony membership may be chemically encoded, and mothers were also chemically similar to their pups, hinting at the possible involvement of phenotype matching in mother-offspring recognition. In the current study, we generated and analyzed chemical data from a non-overlapping sample of 50 mother-offspring pairs from the same two colonies 5 years later. The original results were corroborated in both hypothesis testing and estimation contexts, with p-values remaining highly significant and effect sizes, standardized between studies by bootstrapping the chemical data over individuals, being of comparable magnitude. However, exact replication studies are only capable of showing whether a given effect can be replicated in a specific setting. We therefore investigated whether chemical signatures are colony-specific in general by expanding the geographic coverage of our study to include pups from a total of six colonies around Bird Island. We detected significant chemical differences in all but a handful of pairwise comparisons between colonies. This finding adds weight to our original conclusion that colony membership is chemically encoded, and suggests that chemical patterns of colony membership not only persist over time but can also be generalized over space. Our study systematically confirms and extends our previous findings, while also implying more broadly that spatial and temporal heterogeneity need not necessarily negate the reproduction and generalization of ecological research findings.

Effects of time–depth recorders on maternal foraging and attendance behavior of Antarctic fur seals (Arctocephalus gazella)

1995 ◽  
Vol 73 (8) ◽  
pp. 1538-1544 ◽  
Author(s):  
Brian G. Walker ◽  
Peter L. Boveng
Keyword(s):  
Statistical Power ◽  
Small Sample ◽  
Arctocephalus Gazella ◽  
Marine Animals ◽  
Nursing Visit ◽  
Fur Seals ◽  
Instrument Type ◽  
Variable Nature ◽  
Radio Transmitters ◽  
Antarctic Fur Seals

We evaluated the difference in average durations of foraging trips and nursing visits to shore between one group of female Antarctic fur seals (Arctocephalus gazella) carrying radio transmitters only and another group carrying time–depth recorders (TDRs) and radio transmitters during their first five postpartum foraging trip – nursing visit cycles. Data were collected from 105 different fur seals in five breeding seasons (1989 – 1990 to 1993 – 1994) on Seal Island, Antarctica. Average foraging-trip and nursing-visit durations were significantly greater for the seals carrying TDRs and radio transmitters than for seals carrying radio transmitters only (two-way ANOVA, year × instrument type; trip, P = 0.004; visit, P = 0.04). Historically, instrument-effect studies on marine animals have focused on smaller species and larger instrument to body size ratios. Because of small sample sizes (the number of instruments successfully deployed and retrieved) and the typically variable nature of data from TDRs, the statistical power to detect significant differences due to instrument effects has been low. The evidence of instrument effects on Antarctic fur seals has possible implications for studies utilizing devices attached to similar-sized animals: results may not be representative of the natural (non-instrumented) population.

The inevitability of digital transfer

2019 ◽  
Vol 29 (1/2) ◽  
pp. 224-239 ◽  
Author(s):  
Lale Özdemir
Keyword(s):  
Major Change ◽  
Target Population ◽  
Small Sample ◽  
Original Research ◽  
Content Type ◽  
Transfer Rule ◽  
National Archives ◽  
Research Findings ◽  
The Uk ◽  
Public Bodies

Purpose This paper aims to assess how prepared public bodies are for the transfer of born-digital records to the National Archives (TNA) of the UK in line with the reduction in the transfer rule from 30 to 20 years. Design/methodology/approach The change in the transfer rule means that records of UK public bodies will be transferred to TNA for permanent preservation at 20 years as opposed to 30 years old. This move, which has been described as a major change that is going to be introduced in a manageable and affordable way (20-year rule, The National Archives), will inevitably witness the transfer of born-digital records to the archives much earlier than would have been the case if the change in the transfer rule had not been made. This paper reports on research carried out in the winter of 2017 on the extent to which UK public bodies are prepared for the transfer of born-digital records to TNA. Research was based on a survey of 23 public bodies which included ministries, charities and non-departmental public bodies. The target population was predominantly public bodies that had the highest level of transfer of records to TNA. The justification for this lies in the fact that these bodies, amongst others, transfer the most records to TNA, thus it would be interesting to gain an insight into how prepared these relatively larger public bodies are with regard to born-digital transfer. The remaining public bodies were chosen randomly amongst non-ministerial departments. The primary areas under analysis are plans of public bodies for the transfer of born-digital records, processes for transfer to be undertaken such as selection, appraisal etc., the use of technology in sensitivity review and the trigger date for the transfer of records. Findings An analysis of the research findings found that while a few UK public bodies surveyed had transferred datasets within the framework of the TNA Government Datasets (NDAD) initiative or as part of an inquiry, only one public body had transferred other born-digital records to TNA. The findings also reveal that most public bodies are yet to plan for, or to adjust, their current archival processes to take into account the different mind-set and skills required for the transfer of born-digital records. The level of preparedness is therefore limited primarily because public bodies have yet to undertake a transfer of born-digital records to the archives. The research findings also revealed that public bodies had not as yet made adjustments or changes to current practice to take into account the issues relating to the processing of born-digital records prior to transfer. Research limitations/implications The findings of the research at hand are based on a survey submitted electronically to twenty-three public bodies with the aim of assessing how prepared they are for the transfer of born-digital records to the National Archives (TNA). The survey was sent to 27 public bodies with responses received by 23 public bodies. The survey sent to these bodies comprises eight questions that were deemed to be important in the current digital landscape with regard to the processes involved in the transfer of records, beginning from their creation. Thus, an element of subjectivity exists with regard to the outcome of the research, as the public bodies chosen were guided in prioritising any issues about digital transfer through the questions posed. The research carried out is also limited in that it focuses primarily on ministerial departments (14 of the 23 surveyed) and also constitutes a very small sample of UK public bodies overall. However, the originality of the data obtained through the study carried out by far outweighs the limitations of the research methodology. Originality/value This paper highlights that the transfer of born-digital records through original research amongst the 23 public bodies surveyed is not widespread, and that processes and procedures specifically for the management of processes for born-digital records are yet to be implemented. The study concludes that long-term planning for the transfer of born-digital records is yet to be undertaken and that public bodies are more likely to deal with the issue when their digital records are closer to reaching the point of transfer.

Are Most Published Research Findings False?

2011 ◽  
Vol 231 (5-6) ◽  
Author(s):  
Andreas Diekmann
Keyword(s):  
Statistical Tests ◽  
Total Error ◽  
A Priori ◽  
Short Note ◽  
Original Research ◽  
Replication Studies ◽  
Professional Journals ◽  
Error Ratio ◽  
Research Findings

SummaryIn a provocative article Ioannidis (2005) argues that, in disciplines employing statistical tests of significance, professional journals report more wrong than true significant results. This short note sketches the argument and explores under what conditions the assertion holds. The “positive predictive value” (PPV) is lower than 1/2 if the a priori probability of the truth of a hypothesis is low. However, computation of the PPV includes only significant results. If both significant and non-significant results are taken into account the “total error ratio” (TER) will not exceed 1/2 provided no extremely large publication bias is present. Moreover, it is shown that theory-driven research may reduce the proportion of errors. Also, the role of replications is emphasized; replication studies of original research are so important because they drastically decrease the error ratio.

scholarly journals Assessing and improving robustness of psychological research findings in four steps.

2021 ◽  
Author(s):  
Michele B. Nuijten
Keyword(s):  
Psychological Research ◽  
Alternative Strategy ◽  
Replication Studies ◽  
Psychological Science ◽  
Replication Crisis ◽  
Research Findings ◽  
Efficient Alternative ◽  
Robustness Check ◽  
Over Time

Increasing evidence indicates that many published findings in psychology may be overestimated or even false. An often-heard response to this “replication crisis” is to replicate more: replication studies should weed out false positives over time and increase robustness of psychological science. However, replications take time and money – resources that are often scarce. In this chapter, I propose an efficient alternative strategy: a four-step robustness check that first focuses on verifying reported numbers through reanalysis before replicating studies in a new sample.

scholarly journals Are Difficult-To-Study Populations too Difficult to Study in a Reliable Way?

2020 ◽  
Vol 25 (1) ◽  
pp. 41-50 ◽  
Author(s):  
Florian Lange
Keyword(s):  
Statistical Power ◽  
Scientific Evidence ◽  
Statistical Significance ◽  
Neuropsychological Test ◽  
Small Sample ◽  
Selective Reporting ◽  
Test Procedures ◽  
Psychological Phenomena ◽  
Replication Studies ◽  
Methodological Choices

Abstract. Replication studies, pre-registration, and increases in statistical power will likely improve the reliability of scientific evidence. However, these measures face critical limitations in populations that are inherently difficult to study. Members of difficult-to-study populations (e.g., patients, children, non-human animals) are less accessible to researchers, which typically results in small-sample studies that are infeasible to replicate. Nevertheless, meta-analyses on clinical neuropsychological data suggest that difficult-to-study populations can be studied in a reliable way. These analyses often produce unbiased effect-size estimates despite aggregating across severely underpowered original studies. This finding can be attributed to a neuropsychological research culture involving the non-selective reporting of results from standardized and validated test procedures. Consensus guidelines, test manuals, and psychometric evidence constrain the methodological choices made by neuropsychologists, who regularly report the results from neuropsychological test batteries irrespective of their statistical significance or novelty. Comparable shifts toward more standardization and validation, complete result reports, and between-lab collaborations can allow for a meaningful and reliable study of psychological phenomena in other difficult-to-study populations.

scholarly journals Changing the logic of replication: A case from infant studies

2019 ◽  
Author(s):  
Francesco Margoni ◽  
Martin Shepperd
Keyword(s):  
Statistical Power ◽  
Sampling Error ◽  
Meta Analysis ◽  
Statistical Significance ◽  
Small Sample ◽  
Infant Research ◽  
Replication Studies ◽  
Wide Range ◽  
Small Sample Sizes ◽  
Meta Analyses

Infant research is making considerable progresses. However, among infant researchers there is growing concern regarding the widespread habit of undertaking studies that have small sample sizes and employ tests with low statistical power (to detect a wide range of possible effects). For many researchers, issues of confidence may be partially resolved by relying on replications. Here, we bring further evidence that the classical logic of confirmation, according to which the result of a replication study confirms the original finding when it reaches statistical significance, could be usefully abandoned. With real examples taken from the infant literature and Monte Carlo simulations, we show that a very wide range of possible replication results would in a formal statistical sense constitute confirmation as they can be explained simply due to sampling error. Thus, often no useful conclusion can be derived from a single or small number of replication studies. We suggest that, in order to accumulate and generate new knowledge, the dichotomous view of replication as confirmatory/disconfirmatory can be replaced by an approach that emphasizes the estimation of effect sizes via meta-analysis. Moreover, we discuss possible solutions for reducing problems affecting the validity of conclusions drawn from meta-analyses in infant research.

Depressive Traits and Theory of Mind in Healthy Individuals: A Mediation Study

2018 ◽  
Author(s):  
Nicholas James Rowark
Keyword(s):  
Theory Of Mind ◽  
Executive Functions ◽  
Executive Control ◽  
Statistical Power ◽  
Social Cognitive ◽  
Clinical Sample ◽  
Small Sample ◽  
Future Research ◽  
Healthy Individuals ◽  
Prepotent Response

Depression has been associated with poor social cognitive functioning, including impaired performance on measures of theory of mind. However, the association between depression and theory of mind performance has been removed when controlling for differences in executive functioning, which is also impacted by depression. Among these executive functions, inhibition of prepotent response has been demonstrated as enabling success on theory of mind tests. In the context of these findings, the current investigation tested whether a relationship could be found between depressive traits and theory of mind in a non-clinical sample, and whether this relationship was mediated by differences in executive control of inhibition. Theory of mind was assessed in 31 healthy individuals using an audio-presented false-belief reasoning task, which also tested baseline performance in non-mental-state reasoning. Inhibition of prepotent response was assessed with interference measures on a Stroop colour-word task, and depressive traits were self-reported through the second version of the Beck Depression Inventory. Mediation analysis revealed that executive control of inhibition did not significantly mediate an indirect effect of depressive traits on theory of mind. It was interpreted that relationships previously found between major depression, executive and social-cognitive functions do not generalise beyond clinical boundaries. However, these findings are discussed in terms of the small sample size, limiting statistical power, and several methodological limitations. Future research should assess the relationship between depressive traits and theory of mind using alternative measures of mental representation, or include a neurocognitive battery assessing executive functions other than inhibition.

scholarly journals AB0571 IS RITUXIMAB AN ADEQUATE GLUCOCORTICOID SPARING AGENT IN IDIOPATHIC INFLAMMATORY MYOPATHIES?

2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 1582.1-1582
Author(s):  
B. H. Egeli ◽  
S. Ergun ◽  
Y. K. Gursoy ◽  
A. Cetin ◽  
S. Ugurlu
Keyword(s):  
Disease Activity ◽  
Alternative Treatment ◽  
Statistical Power ◽  
Signs And Symptoms ◽  
Small Sample ◽  
Idiopathic Inflammatory Myopathies ◽  
Inflammatory Myopathies ◽  
Treatment Methods ◽  
Before And After

Background:Idiopathic inflammatory myopathies (IIM) are essentially treated aiming improvement of muscle function and extra muscular disease manifestations. The backbone of the treatment is corticosteroids enhancing the survival and patient quality of life. The lack of consensus on target-specific immunosuppressive treatment highlights the need for further studies evaluating alternative treatment methods. Rituximab is potentially a glucocorticoid-sparing agent which was reviewed in multiple studies with small sample sizes due to the rarity of the disease.Objectives:Higher statistical power can enhance the trustworthiness of alternative treatment methods yielding the main objective of this study.Methods:This retrospective study was conducted at a tertiary rheumatology center. Patients were diagnosed with an idiopathic inflammatory myopathy (dermatomyositis [DM], polymyositis [PM]) and were treated with rituximab in order to be included in this study. Clinical signs and symptoms of the presentation were noted during the first patient encounter as well as the follow-up. Parameters of disease activity including acute phase reactants, muscle enzyme levels, and disease-specific autoantibodies were analyzed.Results:The study includes 28 patients (20 DM, 8 PM). The age of diagnosis was 43.44 ± 15.77 years, follow-up duration was 60.7 ± 70.7 months. The presenting signs and symptoms of the patients are shown in Figure 1. The parameters of disease activity before and after treatment are summarized in Table 1. The mean corticosteroid dose decreased from 31.429 ±23.934 mg to 10.278 ±12.001 (p=0.001). Other treatment methods were methotrexate (n=18), Intravenous Immunoglobulin (IVIG) (n=7), and cyclophosphamide (n=2). There were not any deaths during the follow-up. Two patients were lost to follow-up.Table 1.The Parameters of Disease Activity Before and After TreatmentBefore TreatmentAfter TreatmentP ValueCPK, mean ± std (U/L)1426 ± 2049.92263.44 ± 265.630.004LDH, mean ± std (U/L)557.5 ± 365379.78 ± 192.10.03AST, mean ± std (U/L)62.52 ± 5930.16 ± 27.590.01ALT, mean ± std (U/L)56.48 ± 49.2127.64 ± 24.520.008ESR, mean ± std (mm/hour)26.38 ± 28.9820.39 ± 18.760.36CRP, mean ± std (mg/L)19.23 ± 46.1512.53 ± 26.670.5RF, mean ± std (U/mL)0 (0)N/AN/AANA, n (%)3 (10.71)N/AN/AFigure 1.The Presenting Signs and Symptoms of the PatientsConclusion:Rituximab is shown to be effective in treating myositis along with corticosteroids as well as a corticosteroid-sparing agent in retrospective studies and open-label clinical trials; however, lack of statistical power should be underlined. Long term decrease in steroid use and decrease in disease activity markers hints the effective use of rituximab as a glucocorticoid sparing agent as well as its safety with minimal side effects.Disclosure of Interests:None declared

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