Retractions in Science

Publication plays a pivotal role in the growth and dissemination of scientific knowledge. But the growth of knowledge is neither strictly linear nor unidirectional. Mistakes are made. Retraction is one means by which the scientific record is corrected. In this paper, we examine the retraction practices and prevalence in the journal Science. We focus on 35 years of published retractions, from 1983 to 2017. We are not only concerned with determining the scope of the problem, but also the patterns in the data. From a policy perspective, knowledge of any patterns in retractions may be useful in developing targeted responses to deal with the root causes

Retractions in Science

Publication plays a pivotal role in the growth and dissemination of scientific knowledge. But the growth of knowledge is neither strictly linear nor unidirectional. Mistakes are made. Retraction is one means by which the scientific record is corrected. In this paper, we examine the retraction practices and prevalence in the journal Science. We focus on 35 years of published retractions, from 1983 to 2017. We are not only concerned with determining the scope of the problem, but also the patterns in the data. From a policy perspective, knowledge of any patterns in retractions may be useful in developing targeted responses to deal with the root causes

Evolutionary consequences of DNA methylation in a basal Metazoan

Gene body methylation (gbM) is an ancestral and widespread feature in Eukarya, yet its adaptive value and evolutionary implications remain unresolved. The occurrence of gbM within protein-coding sequences is particularly puzzling, because methylation causes cytosine hypermutability and hence is likely to produce deleterious amino acid substitutions. We investigate this enigma using an evolutionarily basal group of Metazoa, the stony corals (order Scleractinia, class Anthozoa, phylum Cnidaria). We show that patterns of coral gbM are similar to other invertebrate species, predicting wide and active transcription and slower sequence evolution. We also find a strong correlation between gbM and codon bias, resulting from systematic replacement of CpG bearing codons. We conclude that gbM has strong effects on codon evolution and speculate that this may influence establishment of optimal codons

Maternal effects and Symbiodinium community composition drive differential patterns in juvenile survival in the coral Acropora tenuis

Coral endosymbionts in the dinoflagellate genus Symbiodinium are known to impact host physiology and have led to the evolution of reef-building, but less is known about how symbiotic communities in early life-history stages and their interactions with host parental identity shape the structure of coral communities on reefs. Differentiating the roles of environmental and biological factors driving variation in population demographic processes, particularly larval settlement, early juvenile survival and the onset of symbiosis is key to understanding how coral communities are structured and to predicting how they are likely to respond to climate change. We show that maternal effects (that here include genetic and/or effects related to the maternal environment) can explain nearly 24% of variation in larval settlement success and 5–17% of variation in juvenile survival in an experimental study of the reef-building scleractinian coral, Acropora tenuis. After 25 days on the reef, Symbiodinium communities associated with juvenile corals differed significantly between high mortality and low mortality families based on estimates of taxonomic richness, composition and relative abundance of taxa. Our results highlight that maternal and familial effects significantly explain variation in juvenile survival and symbiont communities in a broadcast-spawning coral, with Symbiodinium type A3 possibly a critical symbiotic partner during this early life stage

Life cycle assessment of waste prevention

Waste prevention is part of the solution towards circular economy and sustainable consumption. Electronic equipment is known for containing scarce resources and the recycling of these is seen as important. Long lifetime of some electronic products leads to energy consumption during use phase being the most important process for the total impacts from the life cycle. By preventing waste and extending the lifetime of electronics, resources are kept in the loop for a longer period saving the extraction and use of virgin resources. It should be considered if, keeping scarce resources in the loop, will lead to keeping products having low energy efficiency in the loop. A case study was carried out, assessing the environmental impacts from the use and consumption pattern of refrigerators as the electronic product. The study compared two scenarios providing the same functional unit: Cooling of food (5 degrees Celsius) by a 240L refrigerator for 30 years in Denmark during the period 2015-2045. The full lifetime of the refrigerator was assessed including production, use and waste management. The two scenarios assessed were: 1) use of a refrigerator for 10 years and 2) use of a refrigerator with an extended lifetime of 5 years being in total 15 years of use. Both scenarios were assessed for an old refrigerator with a low energy class and a newer refrigerator with a high energy class. Both scenarios were also assessed with substituting the refrigerator in use with one with the same energy class or with one with a more efficient energy class. The assessment showed that the use phase becomes less important, and the production phase becomes the main contributor to the potential environmental impacts when choosing an electronic product with high energy efficiency. Meaning the extraction and production of materials and the assembling of the refrigerator becomes more important when the energy efficiency during use is high. During the life time of electronics the sealing of refrigerators gets worn and the compressor becomes less efficient. Thereby increasing energy consumption is seen for all kinds of electronic devices during the lifetime. It is described in literature that refrigerators tends to have larger energy loss over time than other electronic devices. Therefore the change of energy consumption of scenario 2 was assessed for the two scenarios to have equal potential environmental impacts. For an old refrigerator with low energy efficiency the energy consumption should only increase by ~15% over a period of 30 years consumption time. For the newer refrigerator the change should be ~49% for the two scenarios to have equal environmental impacts. From the assessment it was concluded that it leads to lower potential environmental impacts to replace an old refrigerator with low energy class after 10 years use by a new refrigerator, and again change this to a more energy efficient one after 10 years use (Scenario 1 with substitution to more efficient energy class), than to reuse an old refrigerator with low energy class (Scenario 2 with substitution to same energy class). The study also concludes that it leads to even lower potential environmental impacts to reuse an old refrigerator and replacing it at the end of life with a new one with high energy efficiency, which is also reused to have an extended lifetime (Scenario 2 with substitution to more efficient energy class). The lowest environmental impacts were found by extending the lifetime of refrigerators (Scenario 2) with high energy efficiency. In this way as less energy as possible is used during the use phase, and resources are kept in the loop for as long as possible

Recovery from bleaching is mediated by threshold densities of background thermo-tolerant symbiont types in a reef-building coral

Sensitive molecular analyses show that most corals host a complement of Symbiodinium genotypes that includes thermotolerant types in low abundance. While tolerant symbiont types are hypothesized to facilitate tolerance to temperature and recovery from bleaching, empirical data on their distribution and relative abundance in corals under ambient and stress conditions are still rare. We quantified visual bleaching and mortality of coral hosts, along with relative abundance of C- and D-type Symbiodinium cells in 82 Acropora millepora colonies from three locations on the Great Barrier Reef transplanted to a central inshore site over a 13 month period. Our analyses reveal dynamic change in symbiont associations within colonies and among populations over time. Coral bleaching and declines in C-but not D-type symbionts were observed in transplanted corals. Survival and recovery of 25% of corals from one population was associated with either initial D-dominance or an increase in D-type symbionts that could be predicted by a minimum pre-stress D:C ratio of 0.003. One-third of corals from this population became D dominated at the bleached stage despite no initial detection of this symbiont type, but failed to recover and died in mid to late summer. These results provide a predictive threshold minimum density of background D-type symbionts in A. millepora, above which survival following extreme thermal stress is increased