In 1980, Steven J. Gould published an essay on the emergence of paleobiology as a nomothetic discipline (Gould 1980), nomothetism referring to the search for general laws or principles. Gould contrasted this with the foundation of paleontology, the idiographic tradition of detailing the history of life from the description of new fossil taxa to the elucidation of the long-term patterns of change through time. Among the pioneers of this nomothetic expansion was Jim Valentine. Here I pay tribute to Jim as one of the first paleobiologists, a colleague, coauthor, and friend, emphasizing his intellectual style and insights as much as his lasting contributions. I have written this in part as a eulogy, a remembrance for those who knew him, but also as an introduction to the continuing relevance of his work for those who may be unfamiliar with it.

Over 40 years ago, Raup and Sepkoski identified five episodes of elevated extinction in the marine fossil record that were thought to be statistically distinct, thus warranting the term the “Big Five” mass extinctions. Since then, the term has become part of standard vocabulary, especially with the naming of the current biodiversity crisis as the “sixth mass extinction.” However, there is no general agreement on which time intervals should be viewed as mass extinctions, in part because the Big Five turn out not to be statistically distinct from background rates of extinction, and in part, because other intervals of time have even higher extinction rates, in the Cambrian and early Ordovician. Nonetheless, the Big Five represent the five largest events since the early Ordovician, including in analyses that attempt to compensate for the incompleteness of the fossil and rock records. In the last 40 years, we have learned a great deal about the causes of many of the major and minor extinction events and are beginning to unravel the mechanisms that translated the initial environmental disturbances into extinction. However, for many of the events, further understanding will require going back to the outcrop, where the patchy distribution of environments and pervasive temporal gaps in the rock record challenge our ability to establish true extinction patterns. As for the current biodiversity crisis, there is no doubt that the rate of extinction is among the highest ever experienced by the biosphere, perhaps the second highest after the end-Cretaceous bolide impact. However (and fortunately), the absolute number of extinctions is still relatively small – there is still time to prevent this becoming a genuine mass extinction. Given the arbitrariness of calling out the Big Five, perhaps the current crisis should be called the “incipient Anthropocene mass extinction” rather than the “sixth mass extinction.”

Substantial progress has been made in the standardization of nomenclature for paediatric and congenital cardiac care. In 1936, Maude Abbott published her Atlas of Congenital Cardiac Disease, which was the first formal attempt to classify congenital heart disease. The International Paediatric and Congenital Cardiac Code (IPCCC) is now utilized worldwide and has most recently become the paediatric and congenital cardiac component of the Eleventh Revision of the International Classification of Diseases (ICD-11). The most recent publication of the IPCCC was in 2017. This manuscript provides an updated 2021 version of the IPCCC.

The International Society for Nomenclature of Paediatric and Congenital Heart Disease (ISNPCHD), in collaboration with the World Health Organization (WHO), developed the paediatric and congenital cardiac nomenclature that is now within the eleventh version of the International Classification of Diseases (ICD-11). This unification of IPCCC and ICD-11 is the IPCCC ICD-11 Nomenclature and is the first time that the clinical nomenclature for paediatric and congenital cardiac care and the administrative nomenclature for paediatric and congenital cardiac care are harmonized. The resultant congenital cardiac component of ICD-11 was increased from 29 congenital cardiac codes in ICD-9 and 73 congenital cardiac codes in ICD-10 to 318 codes submitted by ISNPCHD through 2018 for incorporation into ICD-11. After these 318 terms were incorporated into ICD-11 in 2018, the WHO ICD-11 team added an additional 49 terms, some of which are acceptable legacy terms from ICD-10, while others provide greater granularity than the ISNPCHD thought was originally acceptable. Thus, the total number of paediatric and congenital cardiac terms in ICD-11 is 367. In this manuscript, we describe and review the terminology, hierarchy, and definitions of the IPCCC ICD-11 Nomenclature. This article, therefore, presents a global system of nomenclature for paediatric and congenital cardiac care that unifies clinical and administrative nomenclature.

The members of ISNPCHD realize that the nomenclature published in this manuscript will continue to evolve. The version of the IPCCC that was published in 2017 has evolved and changed, and it is now replaced by this 2021 version. In the future, ISNPCHD will again publish updated versions of IPCCC, as IPCCC continues to evolve.

The origin of evolutionary novelty involves changes across the biological hierarchy: from genes and cells to whole organisms and ecosystems. Understanding the mechanisms behind the establishment of new designs involves integrating scientific disciplines that use different data and, often, different means of testing hypotheses. Discoveries from both paleontology and developmental genetics have shed new light on the origin of morphological novelties. The genes that play a major role in establishing the primary axes of the body and appendages, and that regulate the expression of the genes that are responsible for initiating the making of structures such as eyes, or hearts, are highly conserved between phyla. This implies that it is not new genes, per se, that underlie much of morphological innovation, but that it is changes in when and where these and other genes are expressed that constitute the underlying mechanistic basis of morphological innovation. Gene duplication is also a source of developmental innovation, but it is possible that it is not the increased number of genes (and their subsequent divergence) that is most important in the evolution of new morphologies; rather it may be the duplication of their regulatory regions that provides the raw material for morphological novelty. Bridging the gap between microevolution and macroevolution will involve understanding the mechanisms behind the production of morphological variation. It appears that relatively few genetic changes may be responsible for most of the observed phenotypic differences between species, at least in some instances. In addition, advances in our understanding of the mechanistic basis of animal development offer the opportunity to deepen our insight into the nature of the Cambrian explosion. With the advent of whole-genome sequencing, we should see accelerated progress in understanding the relationship between the genotype, phenotype, and environment: post-genomics paleontology promises to be most exciting.

Field experiments were conducted in Alabama during 1999 and 2000 to test the hypothesis that any glyphosate-induced yield suppression in glyphosate-resistant cotton would be less with irrigation than without irrigation. Yield compensation was monitored by observing alterations in plant growth and fruiting patterns. Glyphosate treatments included a nontreated control, 1.12 kg ai/ha applied POST at the 4-leaf stage, 1.12 kg/ha applied DIR at the prebloom stage, and 1.12 kg/ha applied POST at 4-leaf and postemergence directed (DIR) at the prebloom cotton stages. The second variable, irrigation treatment, was established by irrigating plots individually with overhead sprinklers or maintaining them under dryland, nonirrigated conditions. Cotton yield and all measured parameters including lint quality were positively affected by irrigation. Irrigation increased yield 52% compared to nonirrigated cotton. Yield and fiber quality effects were independent of glyphosate treatments. Neither yield nor any of the measured variables that reflected whole plant response were influenced by glyphosate treatment or by a glyphosate by irrigation interaction.

Marshall (1995) used the distribution of the endpoints of 50% range extensions added to the stratigraphic ranges of individual taxa to bracket the position of an extinction boundary. Here we describe two improvements to Marshall's method. First, we show that more precise estimates of the position of such a boundary may be obtained using range extensions with confidence levels of less than 50% (e.g., 20%). Second, we introduce a new method of calculating confidence intervals that explicitly takes into account the position of the highest fossil find. Incorporating these improvements leads to confidence intervals for simulated data sets that are approximately four times more precise than those obtained by using Marshall's (1995) original method and approximately twice as precise as those using other published methods. We provide a look-up table that shows for different numbers of taxa the confidence level that should be used to maximize the precision of the estimated position of the extinction boundary, while ensuring that the boundary still lies within the stratigraphic interval bounded by at least one range extension. Unlike some other methods, our method is nonparametric and does not make the restrictive assumption of uniform preservation and recovery potential. We apply the method to Macellari's (1986) ammonite data from the late Cretaceous of Seymour Island, Antarctica.

Medullosa stands apart from most Paleozoic seed plants in its combination of large leaf area, complex vascular structure, and extremely large water-conducting cells. To investigate the hydraulic consequences of these anatomical features and to compare them with other seed plants, we have adapted a model of water transport in xylem cells that accounts for resistance to flow from the lumen, pits, and pit membranes, and that can be used to compare extinct and extant plants in a quantitative way. Application of this model to Medullosa, the Paleozoic coniferophyte Cordaites, and the extant conifer Pinus shows that medullosan tracheids had the capacity to transport water at volume flow rates more comparable to those of angiosperm vessels than to those characteristic of ancient and modern coniferophyte tracheids. Tracheid structure in Medullosa, including the large pit membrane area per tracheid and the high ratio of tracheid diameter to wall thickness, suggests that its xylem cells operated at significant risk of embolism and implosion, making this plant unlikely to survive significant water stress These features further suggest that tracheids could not have furnished significant structural support, requiring either that other tissues supported these plants or that at least some medullosans were vines. In combination with high tracheid conductivity, distinctive anatomical characters of Medullosa such as the anomalous growth of vascular cambium and the large number of leaf traces that enter each petiole base suggest vascular adaptations to meet the evapotranspiration demands of its large leaves. The evolution of highly efficient conducting cells dictates a need to supply structural support via other tissues, both in tracheid-based stem seed plants and in vessel-bearing angiosperms.

The study of ancient biodiversity trends is confounded by biases of the paleontologic record, but standardizing sampling intensity among time intervals can ameliorate sample-size biases. We show that several existing standardization methods are intimately linked to the spatial components of diversity (alpha, the within-assemblage diversity; and beta, the between-assemblage diversity). The subsampling curves generated by these methods can also be generated by various manipulations of alpha and beta, so that one can predict the responses of the methods to specific changes in alpha or beta diversity. The responses of the subsampling methods to changes in total diversity depend on whether measured alpha or measured beta diversity changed. Like biodiversity, sampling consists of a within-sample component (the number of specimens collected per locality) and a between-sample component (the number of localities). Several subsampling methods (rarefaction, OW, O2W) attempt to standardize sampling effort at both levels, although they use no direct information on the former. Instead, they alter sampling intensity at the beta level to compensate for perceived biases at the alpha level. We show that alpha and beta diversity are not so easily interchangeable and that the accuracy of the subsampling methods depends critically on the spatial characteristics of diversity in a data set. Current methods are calibrated only to the abundance-richness characteristics of individual collections, but the amount of beta diversity and the degree to which the rareness/commonness of taxa correlates among samples also strongly affect the accuracy of the subsampling methods. We offer new calibrations based on empirical data sets that account for these factors. Our findings do not support Alroy et al.'s (2001) tentative claim that the taxonomic radiation in the Cenozoic marine realm is an artifact of biased sampling intensity. Their diversity curves that most strongly contradict Sepkoski's traditional Phanerozoic curve are based on a method that overcorrects for local sample-size biases, whereas the remaining curves are either consistent with the traditional curve or ambiguous because of the limited temporal and taxonomic coverage of the analysis. Other factors may bias Sepkoski's curve, but there is insufficient evidence to claim that variations in sampling intensity are the major determinant of its long-term trajectory.

Observed stratigraphic ranges almost always underestimate true longevities. Strauss and Sadler (1987, 1989) provide a method for calculating confidence intervals on the endpoints of local stratigraphic ranges. Their method can also be applied to composite sections; confidence intervals may be placed on times of origin and extinction for entire species or lineages. Confidence interval sizes depend only on the length of the stratigraphic range and the number of fossil horizons. The technique's most important assumptions are that fossil horizons are distributed randomly and that collecting intensity has been uniform over the stratigraphic range. These assumptions are more difficult to test and less likely to be fulfilled for composite sections than for local sections.

Confidence intervals give useful baseline estimates of the incompleteness of the fossil record, even if the underlying assumptions cannot be tested. Confidence intervals, which can be very large, should be calculated when the fossil record is used to assess absolute rates of molecular or morphological evolution, especially for poorly preserved groups. Confidence intervals have other functions: to determine how rich the fossil record has to be before radiometric dating errors become the dominant source of error in estimated times of origin or extinction; to predict future fossil finds; to predict which species with fossil records should be extant; and to assess phylogenetic hypotheses and taxonomic assignments.

The equations for calculating classical confidence intervals on the end points of stratigraphic ranges are based on the restrictive assumption of randomly distributed fossil finds. Herein, a method is presented for calculating confidence intervals on the end-points of stratigraphic ranges that partially relaxes this assumption: the method will work for any continuous distribution of gap sizes, not just those generated by random processes. The price paid for the generality of the new approach is twofold: (1) there are uncertainties associated with the sizes of the confidence intervals, and (2) for large confidence values (e.g., 95%) a rich fossil record is required to place upper bounds on the corresponding confidence intervals. This new method is not universal; like the method for calculating classical confidence intervals it is based on the assumption that there is no correlation between gap size and stratigraphic position. The fossil record of the Neogene Caribbean bryozoan Metrarabdotos is analyzed with the new approach. The equations developed here, like those for classical confidence intervals, should not be applied to stratigraphic ranges based on discrete sampling regimes, such as those typically established from deep-sea drilling cores, though there are exceptions to this rule.

A generalized method for calculating confidence intervals on the position of the true end point of a stratigraphic range when the distributions of fossil horizons is nonrandom is presented. The method requires a quantitative measure of collecting and/or preservation biases with stratigraphic position. This fossil recovery potential function may be based on (among other variables) bedding-plane surface areas, or, given a water depth curve, an a priori estimate of the preservation potential with water depth. The approach assumes that the observed distribution of fossil horizons is consistent with the distribution predicted by the fossil recovery potential function, an assumption that must be tested before the method is applied. Unlike previous methods for calculating confidence intervals on the end points of stratigraphic ranges, this method may be applied when the number of fossil horizons is correlated with stratigraphic position. The approach should only be applied to sections that have been sampled continuously, or approximately continuously. Its efficacy will depend on how accurately fossil recovery potentials can be determined. A method is also presented for estimating the probability that a species became extinct during a major hiatus in the rock record.

A simple quantitative approach is presented for determining the relative importance of climate change and human impact in driving late Quaternary megafaunal extinctions. This method is designed to determine whether climate change or human impact alone can account for these extinctions, or whether both were important, acting independently (additively) and/or synergistically (multiplicatively). This approach is applied to the megafaunal extinction in the Última Esperanza region of southern Chile. In this region, there is a complex pattern of extinction. Records of environmental change include temperature proxies and pollen records that capture the transition from cold grasslands to warmer, moister forests, as well as evidence of initial human arrival. Uncertainty in extinction times and time of human arrival complicates the analysis, as does uncertainty about the size of local human populations, and the nature, strength, and persistence of their impacts through the late Pleistocene and early Holocene. Results of the Ultima Esperanza analysis were equivocal, with evidence for climate- and human-driven extinction, with each operating alone or additively. The results depend on the exact timing of extinctions and human arrival, and assumptions about the kinds of pressures humans put on the megafauna. There was little evidence for positive synergistic effects, while the unexpected possibility of negative synergistic interactions arose in some scenarios. Application of this quantitative approach highlights the need for higher precision dating of the extinctions and human arrival, and provides a platform for sharpening our understanding of these megafaunal extinctions.

In the United States alone, ∼14,000 children are hospitalised annually with acute heart failure. The science and art of caring for these patients continues to evolve. The International Pediatric Heart Failure Summit of Johns Hopkins All Children’s Heart Institute was held on February 4 and 5, 2015. The 2015 International Pediatric Heart Failure Summit of Johns Hopkins All Children’s Heart Institute was funded through the Andrews/Daicoff Cardiovascular Program Endowment, a philanthropic collaboration between All Children’s Hospital and the Morsani College of Medicine at the University of South Florida (USF). Sponsored by All Children’s Hospital Andrews/Daicoff Cardiovascular Program, the International Pediatric Heart Failure Summit assembled leaders in clinical and scientific disciplines related to paediatric heart failure and created a multi-disciplinary “think-tank”. The purpose of this manuscript is to summarise the lessons from the 2015 International Pediatric Heart Failure Summit of Johns Hopkins All Children’s Heart Institute, to describe the “state of the art” of the treatment of paediatric cardiac failure, and to discuss future directions for research in the domain of paediatric cardiac failure.

The fluid flow through the complex hydrospires of the spiraculate blastoid Pentremites rusticus was analyzed using the first high-resolution three-dimensional digital image (and animation) of the hydrospires taken from a serially sectioned specimen. Measurements of the cross-sectional areas within the hydrospires, in conjunction with the Principle of Continuity, were used to infer the relative water velocity throughout the structures. Even though the calyx narrows adorally, the hydrospires expand in size, keeping pace with the increasing volume of water that entered through the hydrospire pores. Thus, the water maintained a relatively constant velocity within the hydrospire canals, 3.4 to 4.5 times the incurrent velocity. The spiracular openings are sufficiently large that no substantial increase in the exit velocity of the seawater would have been achieved unless the spiracular cover plates were used to reduce the size of the spiracular openings, which we infer was probably the case. The three-dimensional images underscore the fact that the two hydrospires that lie under each ambulacrum do not share the same spiracle and are not connected. Thus, we here redefine the term “hydrospire set” to refer to the pair of hydrospires that are connected. A number of anomalous accessory pores and canals were identified in the digital images. This initial study is based on a single specimen, and thus we were unable to determine the full range of variation present in Pentremites rusticus. Nonetheless, the digital image and the application of the Principle of Continuity offer new insights into the form and function of these remarkable respiratory structures.

One of the many contributions paleontology makes to our understanding of the biosphere and its evolution is a direct temporal record of biotic events. However, assuming fossils have been correctly identified and accurately dated, stratigraphic ranges underestimate true temporal ranges: observed first occurrences are too young, and observed last occurrences are too old. Here I introduce the techniques developed for placing confidence intervals on the end-points of stratigraphic ranges. I begin with the analysis of single taxa in local sections – with the simplest of assumptions – random fossilization. This is followed by a discussion of the methods developed to handle the fact that the recovery of fossils is often non-random in space and time. After discussion of how confidence intervals can be used to test for simultaneous origination and extinctions, I conclude with an example application of confidence intervals to unravel the relative importance of background extinction, environmental change and mass extinction of ammonite species at the end of the Cretaceous in western Tethys.

The proposed mechanism for Reducing Emissions from Deforestation and Degradation (REDD+) offers significant potential for conserving forests to reduce negative impacts of climate change. Tanzania is one of nine pilot countries for the United Nations REDD Programme, receives significant funding from the Norwegian, Finnish and German governments and is a participant in the World Bank’s Forest Carbon Partnership Facility. In combination, these interventions aim to mitigate greenhouse gas emissions, provide an income to rural communities and conserve biodiversity. The establishment of the UN-REDD Programme in Tanzania illustrates real-world challenges in a developing country. These include currently inadequate baseline forestry data sets (needed to calculate reference emission levels), inadequate government capacity and insufficient experience of implementing REDD+-type measures at operational levels. Additionally, for REDD+ to succeed, current users of forest resources must adopt new practices, including the equitable sharing of benefits that accrue from REDD+ implementation. These challenges are being addressed by combined donor support to implement a national forest inventory, remote sensing of forest cover, enhanced capacity for measuring, reporting and verification, and pilot projects to test REDD+ implementation linked to the existing Participatory Forest Management Programme. Our conclusion is that even in a country with considerable donor support, progressive forest policies, laws and regulations, an extensive network of managed forests and increasingly developed locally-based forest management approaches, implementing REDD+ presents many challenges. These are being met by coordinated, genuine partnerships between government, non-government and community-based agencies.