Browse Articles

Correction for Nestor et al., Future scientific innovation requires the transformative power of philanthropy

Traveling wave solutions of a hybrid KdV-Burgers equation with arbitrary real coefficients in relation with beam-permeated multi-ion plasma fluids

How can we make sound replication decisions?

Replication and the reported crises impacting many fields of research have become a focal point for the sciences. This has led to reforms in publishing, methodological design and reporting, and increased numbers of experimental replications coordinated across many laboratories. While replication is rightly considered an indispensable tool of science, financial resources and researchers’ time are quite limited. In this perspective, we examine different values and attitudes that scientists can consider when deciding whether to replicate a finding and how. We offer a conceptual framework for assessing the usefulness of various replication tools, such as preregistration.

Ocean hypoxia: The science of climate change in the sea

Poverty–disease–environment traps: Locally tailored solutions and collective action

Climate variability, population growth, and globalization impacting food security in Pakistan

Automating the practice of science: Opportunities, challenges, and implications

Automation transformed various aspects of our human civilization, revolutionizing industries and streamlining processes. In the domain of scientific inquiry, automated approaches emerged as powerful tools, holding promise for accelerating discovery, enhancing reproducibility, and overcoming the traditional impediments to scientific progress. This article evaluates the scope of automation within scientific practice and assesses recent approaches. Furthermore, it discusses different perspectives to the following questions: where do the greatest opportunities lie for automation in scientific practice?; What are the current bottlenecks of automating scientific practice?; and What are significant ethical and practical consequences of automating scientific practice? By discussing the motivations behind automated science, analyzing the hurdles encountered, and examining its implications, this article invites researchers, policymakers, and stakeholders to navigate the rapidly evolving frontier of automated scientific practice.

Identifying the color and absorption band properties of Fe oxides in Danxia red beds by the visible diffuse reflectance spectrum

Environmental variability across space and time drives the recolonization pattern of a historically persecuted large carnivore

Wildlife populations are not static. Intrinsic and extrinsic factors affect individuals, which lead to spatiotemporal variation in population density and range. Yet, dynamics in density and their drivers are rarely documented, due in part to the inherent difficulty of studying long-term population-level phenomena at ecologically meaningful scales. We studied the spatiotemporal density dynamics in a recolonizing large carnivore population, the wolverine Gulo gulo , across the Scandinavian Peninsula over nine years. We fitted open-population spatial capture-recapture models to noninvasive genetic sampling data collected across Norway and Sweden to estimate annual density surfaces and their drivers. This approach allowed us to model sex-specific changes in wolverine density and the effect of landscape-level environmental determinants over time. Our results revealed that, as wolverines successfully recolonized many parts of their historical range in Scandinavia, the relationship with spatial determinants of density has changed over time. We also found support for sex-specific responses of the Scandinavian wolverine to the environmental determinants of density and differences in the temporal dynamics of their relationships, indicating disproportionate recolonization ability and anthropogenic pressures. We observed significant changes in the relationship of female wolverine density with several determinants during the study period, suggesting still ongoing expansion of female wolverines whereas males might have already reached the range limits. These findings show that the Scandinavian wolverine population is still recovering from centuries of persecution and severe range contraction. Our study sheds light on the dynamics and challenges of recolonizing large carnivores in human-dominated landscapes across time and space.

Computer-aided cholelithiasis diagnosis using explainable convolutional neural network

Emergence and evolution of heterocyte glycolipid biosynthesis enabled specialized nitrogen fixation in cyanobacteria

Heterocytes, specialized cells for nitrogen fixation in cyanobacteria, are surrounded by heterocyte glycolipids (HGs), which contribute to protection of the nitrogenase enzyme from oxygen. Diverse HGs preserve in the sediment and have been widely used as evidence of past nitrogen fixation, and structural variation has been suggested to preserve taxonomic information and reflect paleoenvironmental conditions. Here, by comprehensive HG identification and screening of HG biosynthetic gene clusters throughout cyanobacteria, we reconstruct the convergent evolutionary history of HG structure, in which different clades produce the same HGs. We find that rudimentary HG biosynthetic machinery was already present in cyanobacteria before the emergence of heterocytes for functions unrelated to nitrogen fixation and identify HG analogs produced by specific and distantly related nonheterocytous cyanobacteria. These structurally less complex molecules represent precursors of HGs, suggesting that HGs arose after a genomic reorganization and expansion of ancestral biosynthetic machinery, enabling the rise of cyanobacterial heterocytes in an increasingly oxygenated atmosphere. Our results open a chapter in the potential use of diagenetic products of HGs and HG analogs as fossils for reconstructing the evolution of multicellularity and division of labor in cyanobacteria.

Dairy calves provided with environmental enrichment are more active, playful and have fewer feeding interruptions

Abstract Concerns for farm animal welfare have led to the use of environmental enrichment to stimulate natural behaviours and promote positive emotions. In cattle, the provision of brushes is sometimes recommended but their use in calves and the effects they may have are not well established. The use of precision technologies enables the collection of detailed behavioural data that can be used as welfare indicators. Here we use ultra-wideband location sensors to measure activity and play, along with automatic milk feeders to measure feeding. We assessed the effects of stationary brushes on the behaviour of 226 dairy calves for up to 72 days. Half of the calves had access to the brushes for half of the experimental period. Using a mixed-effects linear model we showed that when brushes were present calves had significantly higher activity, fed slower, had fewer interruptions in their meals and spent less time around the feeder, suggesting reduced competition. Furthermore, calves that had access to brushes during the trial were more active and playful, even on days when the brushes were not available, compared to the control group. This finding indicates for the first time that enrichment may have a lasting effect on calf behaviour and welfare.

Electric transportation and electroreception in hummingbird flower mites

Electric fields in terrestrial environments are used by caterpillars to detect their predators, as foraging cues by pollinators, and facilitate ballooning by spiders. This study shows that electric fields facilitate transportation and detection of hummingbirds in a guild of tropical phoretic mites. Hummingbird flower mites feed on nectar and pollen and complete their life cycle inside flowers. Mites colonize new flowers by hitching rides on hummingbird beaks. Flower mites emerge from hummingbird nostrils and disembark when the beak touches a flower. We tested whether flower mites are attracted to unmodulated electrostatic, or to modulated electric fields with amplitudes and frequencies in the range of those previously reported for hummingbirds. In a laboratory setup, mites were only attracted to modulated electric fields. In a choice experiment between positive or negative polarities, mites almost instantaneously chose positive charges, but only when the field was modulated. Mites display questing behavior, moving their front legs toward an electrostatic source. In experiments where we removed one or both front leg tarsi, we show that modulated fields are detected by sensory structures present in the front legs. We also show that flower mites use electrostatic attraction to bridge the gap to the beaks of hummingbirds, for a few milliseconds becoming one of the fastest terrestrial organisms. Our results confirm that hummingbird flower mites evolved an additional sensory modality — electroreception — to quickly detect hummingbirds and use electrostatics to facilitate transportation onto their hosts.

Navajo Sandstone concretions record extended magnetic chronology

Alternative models of funding curiosity-driven research

Funding of curiosity-driven science is the lifeblood of scientific and technological innovation. Various models of funding allocation became institutionalized in the 20th century, shaping the present landscape of research funding. There are numerous reasons for scientists to be dissatisfied with current funding schemes, including the imbalance between funding for curiosity-driven and mission-directed research, regional and country disparities, path-dependency of who gets funded, gender and race disparities, low inter-reviewer reliability, and the trade-off between the effort and time spent on writing or reviewing proposals and doing research. We discuss possible alternative models for dealing with these issues. These alternatives include incremental changes such as placing more weight on the proposals or on the investigators and representative composition of panel members, along with deeper reforms such as distributed or concentrated funding and partial lotteries in response to low inter-reviewer reliability. We also consider radical alternatives to current funding schemes: the removal of political governance and the introduction of international competitive applications to a World Research Council alongside national funding sources. There is likely no single best way to fund curiosity-driven research; we examine arguments for and against the possibility of systematically evaluating alternative models empirically.

Removal of iron and manganese from acidic aqueous solution by pyrite and pyrite-calcium sulfite

Efficient, scalable, and near-nucleotide-resolution profiling of protein occupancy in the genome with deaminases

Dynamic multiday seizure cycles and evolving rhythms in a tetanus toxin rat model of epilepsy

Chronic stress–induced cholesterol metabolism abnormalities promote ESCC tumorigenesis and predict neoadjuvant therapy response

Recent studies have demonstrated that chronic stress can enhance the development of multiple human diseases, including cancer. However, the role of chronic stress in esophageal carcinogenesis and its underlying molecular mechanisms remain unclear. This study uncovered that dysregulated cholesterol metabolism significantly promotes esophageal carcinogenesis under chronic stress conditions. Our findings indicate that the persistent elevation of glucocorticoids induced by chronic stress stimulates cholesterol uptake, contributing to esophageal carcinogenesis. The activated glucocorticoid receptor (GCR) enrichment at the promoter region of High Mobility Group Box 2 (HMGB2) facilitates its transcription. As a transcription coactivator, HMGB2 enhances Sterol Regulatory Element Binding Transcription Factor 1 (SREBF1) transcription and regulates cholesterol metabolism through LDL particle uptake into cells via Low Density Lipoprotein Receptor (LDLR). These results emphasize the significant impact of chronic stress on esophageal carcinogenesis and establish cholesterol metabolism disorder as a crucial link between chronic stress and the development of ESCC. The implications suggest that effectively managing chronic stress may serve as a viable strategy for preventing and treating ESCC.

CRIP1 inhibits cutaneous melanoma progression through TFAM-mediated mitochondrial biogenesis