scholarly journals Genotypic variability enhances the reproducibility of an ecological study

2016 ◽  
Author(s):  
Alexandru Milcu ◽  
Ruben Puga-Freitas ◽  
Aaron M. Ellison ◽  
Manuel Blouin ◽  
Stefan Scheu ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Ecological Study ◽  
Experimental Studies ◽  
Ecological Studies ◽  
Scientific Disciplines ◽  
Microcosm Study ◽  
Laboratory Microcosm ◽  
Controlled Environments ◽  
Growth Chambers ◽  
Study Designs

Many scientific disciplines currently are experiencing a “reproducibility crisis” because numerous scientific findings cannot be repeated consistently. A novel but controversial hypothesis postulates that stringent levels of environmental and biotic standardization in experimental studies reduces reproducibility by amplifying impacts of lab-specific environmental factors not accounted for in study designs. A corollary to this hypothesis is that the deliberate introduction of controlled systematic variability (CSV) in experimental designs can increase reproducibility. We tested this hypothesis using a multi-laboratory microcosm study in which the same ecological experiment was repeated in 14 laboratories across Europe. Each laboratory introduced environmental and genotypic CSV within and among replicated microcosms established in either growth chambers (with stringent control of environmental conditions) or glasshouses (with more variable environmental conditions). The introduction of genotypic CSV led to lower among-laboratory variability in growth chambers, indicating increased reproducibility, but had no significant effect in glasshouses where reproducibility also was lower. Environmental CSV had little effect on reproducibility. Although there are multiple causes for the “reproducibility crisis”, deliberately including genetic variation may be a simple solution for increasing the reproducibility of ecological studies performed in controlled environments.

Ecological studies

2020 ◽  
pp. 113-126
Author(s):  
Jayati Das-Munshi
Keyword(s):  
Ecological Study ◽  
Multilevel Modelling ◽  
Ecological Studies ◽  
Aggregated Data ◽  
Individual Level ◽  
Country Level ◽  
Level Information ◽  
The Individual ◽  
Study Designs ◽  
Over Time

Ecological studies use aggregated data to infer correlation of exposures with outcomes over time, or by place. One of the first examples of an ecological study was Emile Durkheim’s exploration of country-level factors underlying suicide, first published in 1897. Ecological studies have continued to hold an important place in psychiatry, particularly for developing hypotheses. They can also be used to assess the impact of policies on health outcomes over time. There are important limitations associated with ecological study designs, in particular the ability to make causal inferences at the individual level. Multilevel modelling approaches are an important analytic development in the field, which allow the possibility of using group-level information alongside individual-level attributes in analyses. In the first part of this chapter, some examples of ecological studies and their advantages and disadvantages will be introduced. In the second part of this chapter, multilevel modelling techniques will be briefly introduced and discussed with respect to their use in overcoming some of the limitations of geographical ecological studies.

scholarly journals Does the model of additive effect in placebo research still hold true? A narrative review

JRSM Open ◽  
2017 ◽  
Vol 8 (3) ◽  
pp. 205427041668143 ◽  
Author(s):  
Katja Boehm ◽  
Bettina Berger ◽  
Ulrich Weger ◽  
Peter Heusser
Keyword(s):  
Context Effects ◽  
Experimental Studies ◽  
Additive Model ◽  
Drug Effects ◽  
Future Research ◽  
Inclusion Criteria ◽  
Integrative Study ◽  
Additive Relation ◽  
Specific Factors ◽  
Study Designs

Personalised and contextualised care has been turned into a major demand by people involved in healthcare suggesting to move toward person-centred medicine. The assessment of person-centred medicine can be most effectively achieved if treatments are investigated using ‘with versus without’ person-centredness or integrative study designs. However, this assumes that the components of an integrative or person-centred intervention have an additive relationship to produce the total effect. Beecher’s model of additivity assumes an additive relation between placebo and drug effects and is thus presenting an arithmetic summation. So far, no review has been carried out assessing the validity of the additive model, which is to be questioned and more closely investigated in this review. Initial searches for primary studies were undertaken in July 2016 using Pubmed and Google Scholar. In order to find matching publications of similar magnitude for the comparison part of this review, corresponding matches for all included reviews were sought. A total of 22 reviews and 3 clinical and experimental studies fulfilled the inclusion criteria. The results pointed to the following factors actively questioning the additive model: interactions of various effects, trial design, conditioning, context effects and factors, neurobiological factors, mechanism of action, statistical factors, intervention-specific factors (alcohol, caffeine), side-effects and type of intervention. All but one of the closely assessed publications was questioning the additive model. A closer examination of study design is necessary. An attempt in a more systematic approach geared towards solutions could be a suggestion for future research in this field.

scholarly journals The closer to the Europe Union headquarters, the higher risk of COVID-19? Cautions regarding ecological studies of COVID-19

2020 ◽  
Author(s):  
Shuai Li ◽  
Xinyang Hua
Keyword(s):  
European Country ◽  
Ecological Study ◽  
Ecological Fallacy ◽  
Group Level ◽  
Ecological Studies ◽  
Public Concern ◽  
Individual Level ◽  
The Public ◽  
Country Level ◽  
Level Data

AbstractSeveral ecological studies of the coronavirus disease 2019 (COVID-19) have reported correlations between group-level aggregated exposures and COVID-19 outcomes. While some studies might be helpful in generating new hypotheses related to COVID-19, results of such type of studies should be interpreted with cautions. To illustrate how ecological studies and results could be biased, we conducted an ecological study of COVID-19 outcomes and the distance to Brussels using European country-level data. We found that, the distance was negatively correlated with COVID-19 outcomes; every 100 km away from Brussels was associated with approximately 6% to 17% reductions (all P<0.01) in COVID-19 cases and deaths in Europe. Without cautions, such results could be interpreted as the closer to the Europe Union headquarters, the higher risk of COVID-19 in Europe. However, these results are more likely to reflect the differences in the timing of and the responding to the outbreak, etc. between European countries, rather than the ‘effect’ of the distance to Brussels itself. Associations observed at the group level have limitations to reflect individual-level associations – the so-called ecological fallacy. Given the public concern over COVID-19, ecological studies should be conducted and interpreted with great cautions, in case the results would be mistakenly understood.

scholarly journals Designs of studies published in two Brazilian journals of orthopedics and sports medicine, recently indexed in the ISI Web of Science

2009 ◽  
Vol 127 (6) ◽  
pp. 355-358 ◽  
Author(s):  
Rachel Riera
Keyword(s):  
Sports Medicine ◽  
Web Of Science ◽  
Experimental Studies ◽  
Sample Size Calculation ◽  
Allocation Concealment ◽  
Impact Factors ◽  
Isi Web Of Science ◽  
Manual Search ◽  
Study Designs ◽  
De Medicina

CONTEXT AND OBJECTIVE: The methodology and relevance of articles are among the keystones for promoting their citation and increasing journals' impact factors. Study designs appropriate for answering the questions and adequate sample sizes have the aim of reducing the risk of bias. This study evaluated the articles published in two Brazilian journals of orthopedics and sports medicine that were recently indexed in the ISI Web of Science, regarding study design, sample size calculation, randomization and blinding. DESIGN AND SETTING: Descriptive study at Brazilian Cochrane Center. METHODS: Through a manual search, all original manuscripts published in 2007 in Acta Ortopédica Brasileira and Revista Brasileira de Medicina do Esporte were selected and evaluated. RESULTS: All the 60 articles published in Acta Ortopédica Brasileira and the 87 articles in Revista Brasileira de Medicina do Esporte were included and evaluated. The commonest design in Acta Ortopédica Brasileira was experimental studies (n = 19) and in Revista Brasileira de Medicina do Esporte, update or review articles (n =14). Sample calculations were seen in a minority of the articles. None of the eight clinical trials published presented sample calculations or adequate randomization processes. Three were described as blinded, but none described the measures taken to prevent disclosure of the allocation concealment. CONCLUSIONS: Publication of studies of good methodological quality other than review and experimental studies should be strongly encouraged among Brazilian journals, with the aim of increasing their citation and therefore their impact factor.

scholarly journals A willow drawing from 1786: the earliest depiction of intraspecific trait variation in plants?

2020 ◽  
Author(s):  
Ulrich E Stegmann
Keyword(s):  
Environmental Conditions ◽  
18Th Century ◽  
Elevation Gradient ◽  
Experimental Studies ◽  
Fourth Century ◽  
Trait Variation ◽  
Intraspecific Trait Variation ◽  
Bavarian Alps ◽  
In The Wild ◽  
Unidentified Species

Abstract Background and Aims The study of intraspecific trait variation (ITV) in plants has a long history, dating back to the fourth century BC. Its existence was widely acknowledged by the end of the 18th century, although systematic and experimental studies commenced only a century later. However, the historiography of ITV has many gaps, especially with regard to early observations and visual documents. This note identifies an early depiction of plant ITV. Methods The botanical works of Johann Wolfgang von Goethe (1749–1832), a German writer and naturalist, were subjected to close reading. This included all publications and unpublished sources related to botany between 1785 and 1832 (e.g. notes, drafts, diaries, letters, drawings). This material is accessible in the multi-volume historical-critical edition of Goethe’s studies in natural science (Leopoldina-Ausgabe). Key Results A diary entry from 9 September 1786 described changes in leaf morphology along an elevation gradient in the Bavarian Alps. The leaves of an unidentified species of willow (Spix sp.) and gentian (Gentiana sp.) were said to become narrower with increasing elevation; leaves also stood further apart on twigs, and the latter became thinner. A crude drawing of two willow twigs illustrated the differences. Goethe conjectured that the differences were due to environmental conditions. Conclusions Goethe’s notes were anecdotal, and it is unclear whether the observed plant individuals actually belonged to the same species. Nevertheless, the notes represent an early and clear articulation of the hypothesis that changes in environmental conditions can cause ITV in a natural plant population. The drawing may be the earliest visual record of environmentally caused plant ITV in the wild.

Controversies on neuroprotection therapy in non-arteritic anterior ischaemic optic neuropathy

2019 ◽  
Vol 104 (2) ◽  
pp. 153-156
Author(s):  
Sohan Singh Hayreh
Keyword(s):  
Clinical Trials ◽  
Ischaemic Stroke ◽  
Optic Neuropathy ◽  
Experimental Studies ◽  
Therapeutic Strategies ◽  
Ischaemic Optic Neuropathy ◽  
Pubmed Search ◽  
Anterior Ischaemic Optic Neuropathy ◽  
Study Designs

ObjectiveThere has long been a great interest in neuroprotection therapy for ischaemic stroke and various types of optic neuropathies. In view of that, I reviewed the literature on the role of neuroprotection for non-arteritic anterior ischaemic optic neuropathy (NA-AION).MethodsThe review is based on a PubMed search of literature about the use of neuroprotectors in stroke and optic neuropathies and about current clinical trials of RPh201 and QPI-1007 in NA-AION.ResultsSeveral neuroprotection agents for ischaemic stroke and various types of optic neuropathies have been evaluated extensively in experimental studies in animals and benefits claimed. However, translation of therapeutic strategies for neuroprotection from experimental research to humans has invariably been fraught with failure. Two currently ongoing studies dealing with neuroprotection by RPh201 and QPI-1007 in NA-AION may have limitations in their rationale and study designs.ConclusionsUnfortunately, in spite of all the experimental and clinical research on neuroprotection agents in NA-AION so far, we have no scientifically proven evidence of neuroprotection agents showing any benefit in the human clinical studies so far.

scholarly journals Quasi-experimental study designs series—paper 8: identifying quasi-experimental studies to inform systematic reviews

2017 ◽  
Vol 89 ◽  
pp. 67-76 ◽  
Author(s):  
Julie Glanville ◽  
John Eyers ◽  
Andrew M. Jones ◽  
Ian Shemilt ◽  
Grace Wang ◽  
...  
Keyword(s):  
Experimental Study ◽  
Systematic Reviews ◽  
Experimental Studies ◽  
Quasi Experimental ◽  
Study Designs

Experimental studies of the monocrystal and polycrystal characteristics of silicon photovoltaic modules under environmental conditions of Tashkent

2017 ◽  
Vol 53 (1) ◽  
pp. 23-30 ◽  
Author(s):  
N. A. Matchanov ◽  
A. M. Mirzabaev ◽  
B. R. Umarov ◽  
M. A. Malikov ◽  
A. U. Kamoliddinov ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Experimental Studies ◽  
Photovoltaic Modules
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