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Abstract Background The nematode Caenorhabditis elegans is a major laboratory model in biology. Only ten Caenorhabditis species were available in culture at the onset of this study. Many of them, like C. elegans, were mostly isolated from artificial compost heaps, and their more natural habitat was unknown. Results Caenorhabditis nematodes were found to be proliferating in rotten fruits, flowers and stems. By collecting a large worldwide set of such samples, 16 new Caenorhabditis species were discovered. We performed mating tests to establish biological species status and found some instances of semi-fertile or sterile hybrid progeny. We established barcodes for all species using ITS2 rDNA sequences. By obtaining sequence data for two rRNA and nine protein-coding genes, we determined the likely phylogenetic relationships among the 26 species in culture. The new species are part of two well-resolved sister clades that we call the Elegans super-group and the Drosophilae super-group. We further scored phenotypic characters such as reproductive mode, mating behavior and male tail morphology, and discuss their congruence with the phylogeny. A small space between rays 2 and 3 evolved once in the stem species of the Elegans super-group; a narrow fan and spiral copulation evolved once in the stem species of C. angaria, C. sp. 8 and C. sp. 12. Several other character changes occurred convergently. For example, hermaphroditism evolved three times independently in C. elegans, C. briggsae and C. sp. 11. Several species can co-occur in the same location or even the same fruit. At the global level, some species have a cosmopolitan distribution: C. briggsae is particularly widespread, while C. elegans and C. remanei are found mostly or exclusively in temperate regions, and C. brenneri and C. sp. 11 exclusively in tropical zones. Other species have limited distributions, for example C. sp. 5 appears to be restricted to China, C. sp. 7 to West Africa and C. sp. 8 to the Eastern United States. Conclusions Caenorhabditis are "fruit worms", not soil nematodes. The 16 new species provide a resource and their phylogeny offers a framework for further studies into the evolution of genomic and phenotypic characters.

This article discusses a study conducted to determine the shelter-seeking plans of residents in tornado-impacted neighborhoods of Tuscaloosa in Alabama for a future tornado event. Researchers learned that many residents intend to change their shelter plan to a safer option. They also learned that many residents responded that they did not know their exact future plans.

Much progress has been made in understanding how the brain combines signals from the two eyes. However, most of this work has involved achromatic (black and white) stimuli, and it is not clear if the same processes apply in color-sensitive pathways. In our first experiment, we measured contrast discrimination ("dipper") functions for four key ocular configurations (monocular, binocular, half-binocular, and dichoptic), for achromatic, isoluminant L-M and isoluminant S-(L+M) sine-wave grating stimuli (L: long-, M: medium-, S: short-wavelength). We find a similar pattern of results across stimuli, implying equivalently strong interocular suppression within each pathway. Our second experiment measured dichoptic masking within and between pathways using the method of constant stimuli. Masking was strongest within-pathway and weakest between S-(L+M) and achromatic mechanisms. Finally, we repeated the dipper experiment using temporal luminance modulations, which produced slightly weaker interocular suppression than for spatially modulated stimuli. We interpret our results in the context of a contemporary two-stage model of binocular contrast gain control, implemented here using a hierarchical Bayesian framework. Posterior distributions of the weight of interocular suppression overlapped with a value of 1 for all dipper data sets, and the model captured well the pattern of thresholds from all three experiments.

The U.S. federal government is unbalanced in its capacity to recognize, manage, and engage cultural heritage as part of its response to climate change. Legislation from the 1906 Antiquities Act to Executive Order (EO) 13990 signed in 2021 has set an overarching approach in which heritage is understood to be primarily tangible places and things that should be conserved, foremost through monument and park boundaries and significance designations. Such conservation, however, does not protect heritage from impacts of climate change and how to manage these components of heritage is nearly invisible in recent climate-focused publications of the two agencies assigned by legislation to serve as leads for cultural heritage in the U.S. government. Yet further, the long-standing tangible approach to heritage does not incorporate emerging understandings of its intangible components and the diverse connections of all forms of heritage to place, meaning, identity, and global change goals of sustainability and equity. In contrast, analysis of 27 federal agency climate adaptation plans prepared in response to 2021 EO 14008 shows that multiple agencies not assigned lead roles for heritage recognize a range of responsibilities that include heritage as part of climate adaptation, mitigation, equity, and coordination with Indigenous communities. This paper explores U.S. heritage legislative history, the definition it helped create for heritage, more recent understandings of heritage, and relationships of these to climate change and how these are represented in climate work and plans across U.S. federal agencies. On these bases, recommendations are provided for research and policy steps., Competing Interests: Competing interests statement:The author declares no competing interest.

There is a growing recognition that responding to climate change necessitates urban adaptation. We sketch a transdisciplinary research effort, arguing that actionable research on urban adaptation needs to recognize the nature of cities as social networks embedded in physical space. Given the pace, scale and socioeconomic outcomes of urbanization in the Global South, the specificities and history of its cities must be central to the study of how well-known agglomeration effects can facilitate adaptation. The proposed effort calls for the co-creation of knowledge involving scientists and stakeholders, especially those historically excluded from the design and implementation of urban development policies., Competing Interests: Competing interestsThe authors declare no competing interests., (© The Author(s) 2023.)

The spindle shows remarkable diversity, and changes in an integrated fashion, as cells vary over evolution. Here, we provide a mechanistic explanation for variations in the first mitotic spindle in nematodes. We used a combination of quantitative genetics and biophysics to rule out broad classes of models of the regulation of spindle length and dynamics, and to establish the importance of a balance of cortical pulling forces acting in different directions. These experiments led us to construct a model of cortical pulling forces in which the stoichiometric interactions of microtubules and force generators (each force generator can bind only one microtubule), is key to explaining the dynamics of spindle positioning and elongation, and spindle final length and scaling with cell size. This model accounts for variations in all the spindle traits we studied here, both within species and across nematode species spanning over 100 million years of evolution., Competing Interests: RF, CY, GF, HW, DS, MR, TM, MS, DN No competing interests declared, (© 2020, Farhadifar et al.)

Climate science has outlined targets for reductions of greenhouse gas emissions necessary to provide a substantial chance of avoiding the worst impacts of climate change on both natural and human systems. How to reach those targets, however, requires balancing physical realities of the natural environment with the complexity of the human social environment, including histories, cultures, and values. Archaeology is the study of interactions of natural and social environments through time and across space. As well, the field of cultural resources management, which includes archaeology, regularly engages with values such as site significance and allocation of funding that the modern social environment ascribes to its own history. Through these two approaches, archaeology has potential to provide both data for and methods of addressing challenges the global community faces through climate change. To date, however, archaeology and related areas of cultural heritage have had relatively little role in the global climate response. Here, we assess the social environment of archaeology and climate change and resulting structural barriers that have limited use of archaeology in and for climate change with a case study of the US federal government. On this basis, we provide recommendations to the fields of archaeology and climate response about how to more fully realize the multiple potential uses of archaeology for the challenges of climate change., Competing Interests: Competing interest statement: M.R. is working on a consulting basis with ICOMOS on a project to more fully represent cultural heritage in reports of the IPCC.

The varied effects of recent extreme weather events around the world exemplify the uneven impacts of climate change on populations, even within relatively small geographic regions. Differential human vulnerability to environmental hazards results from a range of social, economic, historical, and political factors, all of which operate at multiple scales. While adaptation to climate change has been the dominant focus of policy and research agendas, it is essential to ask as well why some communities and peoples are disproportionately exposed to and affected by climate threats. The cases and synthesis presented here are organized around four key themes (resource access, governance, culture, and knowledge), which we approach from four social science fields (cultural anthropology, archaeology, human geography, and sociology). Social scientific approaches to human vulnerability draw vital attention to the root causes of climate change threats and the reasons that people are forced to adapt to them. Because vulnerability is a multidimensional process rather than an unchanging state, a dynamic social approach to vulnerability is most likely to improve mitigation and adaptation planning efforts. This article is categorized under:Vulnerability and Adaptation to Climate Change > Values-Based Approach to Vulnerability and Adaptation., Competing Interests: The authors have declared no conflicts of interest for this article.

We addressed phylogenetic relationships among species of Planipapillus, a clade of oviparous onychophorans from southeastern mainland Australia, to create a framework for understanding the evolution of the modified male head papillae used in mating in this clade. We sequenced fragments of two mitochondrial genes, COI and 12S rRNA, and a nuclear intron from the fushi tarazu gene, for individuals from 14 putative species of Planipapillus and six outgroups. We analyzed these data under both parsimony and likelihood criteria, incorporating heterogeneous parameter fitting guided by likelihood ratio tests. These analyses result in strong, congruent support for many clades. We infer multiple independent origins of spikes in Planipapillus male head structures., (Copyright 2001 Academic Press.)