Extreme Specialization Research Articles

Production network structure, specialization and unemployment: Measuring the structural resilience of national economies

Specialization leads to efficient production structures that generate welfare gains, while the resulting interconnectedness of countries spreads shocks more rapidly, making the global economic system more volatile. This paper applies the framework of ecological network analysis to input–output data and captures resilient economic structures between self-sufficiency (redundancy) and extreme specialization (efficiency). Calculating the structural resilience of 69 countries shows that economies are more redundant than ecological systems and moved towards more efficient structures over time. By regressing economic openness on structural characteristics, we find that economically more open economies on the export side are more efficient and less structurally redundant. This reflects that specialization and integration into global supply chains go hand in hand. We also find a significant empirical relationship between structural resilience and changes in unemployment. This finding suggests that measuring the structural resilience of national production networks helps capture the robustness of economic systems.

Trades-offs between pollinator attraction and florivore defense maximize reproductive success in the self-incompatible Rivea ornata (Convolvulaceae)

BackgroundRivea ornata, a rare species from the morning glory family, exhibits uncommon characteristics compared to other typical morning glories, including nocturnal flowers that fit the classic moth pollination syndrome. However, the accuracy of its predicted pollination syndrome and its mating system have never been assessed. Additionally, R. ornata flowers attract not only pollinators but also florivores, potentially reducing plant reproductive success. Therefore, this study examined two populations of R. ornata in Thailand and assessed traits related to pollinator attraction and reward, determined its mating system, identified floral visitors and effective pollinators, and investigated the effect of florivory on reproductive success.ResultsRivea ornata is highly fertile but self-incompatible and an obligate outcrosser, rendering it highly dependent on pollinators. Lepidopterans, particularly nocturnal hawk moths, were found to account for a significant proportion of all visits and were the sole effective pollinators of this plant species, in correspondence with its predicted pollination syndrome. Surprisingly, florivory did not significantly reduce reproductive success. This phenomenon may be explained by the strategies employed by R. ornata, which align with the optimal defense hypothesis and functional trade-offs. Specifically, R. ornata appears to invest resources in defending key floral structures while, simultaneously, guard ants are conspicuously absent from flowers, resulting in some florivore damage to non-vital floral organs but ensuring that pollinators are not deterred by ants and thus maintaining high pollinator visitation rates.ConclusionsOur findings indicate that reproduction-related traits in R. ornata, including those involved in pollinator attraction and reward and florivore defense, are highly effective and work in concert to maximize plant reproductive success. Therefore, a main risk that R. ornata faces is the decline or disappearance of hawk moths and other lepidopterans given its extreme specialization and high dependence on pollinators, and conservation efforts should include habitat protection for both R. ornata and its pollinators.

The Localization of Cell Wall Components in the Quadrifids of Whole-Mount Immunolabeled Utricularia dichotoma Traps.

Utricularia (bladderworts) are carnivorous plants. They produce small hollow vesicles, which function as suction traps that work underwater and capture fine organisms. Inside the traps, there are numerous glandular trichomes (quadrifids), which take part in the secretion of digestive enzymes, the resorption of released nutrients, and likely the pumping out of water. Due to the extreme specialization of quadrifids, they are an interesting model for studying the cell walls. This aim of the study was to fill in the gap in the literature concerning the immunocytochemistry of quadrifids in the major cell wall polysaccharides and glycoproteins. To do this, the localization of the cell wall components in the quadrifids was performed using whole-mount immunolabeled Utricularia traps. It was observed that only parts (arms) of the terminal cells had enough discontinuous cuticle to be permeable to antibodies. There were different patterns of the cell wall components in the arms of the terminal cells of the quadrifids. The cell walls of the arms were especially rich in low-methyl-esterified homogalacturonan. Moreover, various arabinogalactan proteins also occurred. Cell walls in glandular cells of quadrifids were rich in low-methyl-esterified homogalacturonan; in contrast, in the aquatic carnivorous plant Aldrovanda vesiculosa, cell walls in the glandular cells of digestive glands were poor in low-methyl-esterified homogalacturonan. Arabinogalactan proteins were found in the cell walls of trap gland cells in all studied carnivorous plants: Utricularia, and members of Droseraceae and Drosophyllaceae.

The morphological paradigm in robotics

In the paper, we are going to show how robotics is undergoing a shift in a bionic direction after a period of emphasis on artificial intelligence and increasing computational efficiency, which included isolation and extreme specialization. We assemble these new developments under the label of the morphological paradigm.The change in its paradigms and the development of alternatives to the principles that dominated robotics for a long time contains a more general epistemological significance. The role of body, material, environment, interaction and the paradigmatic status of biological and evolutionary systems for the principles of control are crucial here. Our focus will be on the introduction of the morphological paradigm in a new type of robotics and to contrast the interests behind this development with the interests shaping former models. The article aims to give a clear account of the changes in principles of orientation and control as well as concluding general observation in terms of historical epistemology, suggesting further political-epistemological analysis.

The comparative morphology of the musculature controlling the pectoral free rays in scorpaenoid fishes.

Free rays are ventral pectoral fin rays (lepidotrichia) that are free of the pectoral fin webbing. They are some of the most striking adaptations of benthic fishes. Free rays are used for specialized behaviors such as digging, walking or crawling along the sea bottom. Studies of pectoral free rays have focused on a small number of species, most notably the searobins (Family Triglidae). Previous research on the morphology of the free rays has emphasized their functional novelty. We hypothesize that the more extreme specializations of the pectoral free rays in searobins are not precisely novel, but are part of a broader range of morphological specializations that are associated with the pectoral free rays in suborder Scorpaenoidei. We perform a detailed comparative description of the intrinsic musculature and osteology of the pectoral free rays in three families of scorpaenoid fishes: Hoplichthyidae, Triglidae, and Synanceiidae. These families vary in the number of pectoral free rays and the degree of morphological specialization of those rays. As part of our comparative analysis, we propose significant revisions to earlier descriptions of both the identity and function of the musculature associated with the pectoral free rays. We focus particularly on the specialized adductors that are important for walking behaviors. Our emphasis on the homology of these features provides important morphological and evolutionary context for understanding the evolution and function of free rays within Scorpaenoidei and other groups.

Faustian bargains: Short-term and long-term contingencies in phylogeny, ontogeny, and sociogeny.

Rachlin's interpretations of self-control depend on the short-term versus the long-term consequences of behavior. Sometimes these effects support each other (typing an abstract produces a written product now and is later read by others). Sometimes they conflict (procrastination now is incompatible with finishing the abstract by deadline). We usually reserve the language of self-control for human cases where long-term consequences are chosen over short-term ones. Rachlin made this distinction salient in ontogeny, but it also applies to selection in phylogeny (Darwinian evolution) and sociogeny (behavior passed from one organism to another). Our account examines relations between short-term and long-term consequences at each level of selection. For example, sexual selection has adaptive, short-term mating consequences but may drive species to extreme specializations that jeopardize long-term survival. In sociogeny, as in the Tragedy of the Commons, group members may get immediate economic benefits from exploiting resources but exhaust those resources over the long term. Whatever the level, when short-term and long-term consequences have opposing effects, adaptive behavior may depend on whether temporally extended contingencies exert more control than more immediate benefits.

Cranial remains of Ramsayia magna from the Late Pleistocene of Australia and the evolution of gigantism in wombats (Marsupialia, Vombatidae)

AbstractGiant wombats (defined here as ≥70 kg) are found in the genera Phascolonus, Ramsayia and perhaps Sedophascolomys. Ramsayia is currently the most poorly known, having been described from mandibular and cranial fragments. Here, we report the most complete cranial remains attributable to the genus, identified as R. magna. The specimen provides new insights into the anatomy of the species and evolutionary adaptations to gigantism in Vombatidae. We record parietal sinuses in a vombatid for the first time, an adaptation to increased skull size relative to the braincase. The presence of a prominent premaxillary spine may indicate that the species possessed a large, fleshy nose. Both features are convergent on other large‐bodied, non‐vombatid extinct megaherbivores of Australia such as Diprotodon optatum. We use the cranial remains to examine the phylogenetic relationships of giant wombats to other vombatids. Phylogenetic analysis using maximum parsimony and Bayesian inference indicates that Phascolomys, Ramsayia and Sedophascolomys form a clade, suggesting a single origin of gigantism within Vombatidae. This origin may be related to the exploitation of poor‐quality foods, and preceded extreme specializations observed in the cranial anatomy of the giant wombats. U‐series and combined U‐series and electron spin resonance (ESR) dating methods were applied to one fossil tooth. Age calculations systematically correlate the fossil remains to Marine Isotope Stage 5, and an age of c. 80 000 years can be proposed for this specimen. With only a single well‐dated occurrence for this taxon, it is currently impossible to determine when and why R. magna became extinct.

Phylogenetic resolution of the fly superfamily Ephydroidea-Molecular systematics of the enigmatic and diverse relatives of Drosophilidae.

The schizophoran superfamily Ephydroidea (Diptera: Cyclorrhapha) includes eight families, ranging from the well-known vinegar flies (Drosophilidae) and shore flies (Ephydridae), to several small, relatively unusual groups, the phylogenetic placement of which has been particularly challenging for systematists. An extraordinary diversity in life histories, feeding habits and morphology are a hallmark of fly biology, and the Ephydroidea are no exception. Extreme specialization can lead to “orphaned” taxa with no clear evidence for their phylogenetic position. To resolve relationships among a diverse sample of Ephydroidea, including the highly modified flies in the families Braulidae and Mormotomyiidae, we conducted phylogenomic sampling. Using exon capture from Anchored Hybrid Enrichment and transcriptomics to obtain 320 orthologous nuclear genes sampled for 32 species of Ephydroidea and 11 outgroups, we evaluate a new phylogenetic hypothesis for representatives of the superfamily. These data strongly support monophyly of Ephydroidea with Ephydridae as an early branching radiation and the placement of Mormotomyiidae as a family-level lineage sister to all remaining families. We confirm placement of Cryptochetidae as sister taxon to a large clade containing both Drosophilidae and Braulidae–the latter a family of honeybee ectoparasites. Our results reaffirm that sampling of both taxa and characters is critical in hyperdiverse clades and that these factors have a major influence on phylogenomic reconstruction of the history of the schizophoran fly radiation.

Divergence Dating and Biogeography of Xenosauridae Including Fossils as Terminal Taxa

Middle-American knob scaled lizards of the genus Xenosaurus are viviparous lizards characterized by flattened bodies, peculiar knob-like scales, and extreme specialization to a crevice-dwelling ecology. Species within this rarely seen and enigmatic genus are distributed throughout much of Mexico and Guatemala. Xenosaurus is the sole surviving genus of the ancient family Xenosauridae and little is known about the origins and biogeographic history of members of the group. To address this deficit, we estimated divergence times across Xenosaurus under the fossilized birth–death model, including published ddRADseq data, morphological data for six extant and three fossil relatives to genus Xenosaurus, and fossil occurrence data for the three fossil relatives. Crown Xenosaurus was estimated to be 35 million years old, considerably younger than the stem age of the family, implying high rates of extinction. The distribution of Xenosaurus populations across Mexico and the location of the three fossil relatives in western North America suggest a Nearctic origin with a north to southeast direction of range evolution in Xenosaurus. To test this hypothesis, we performed a Bayesian biogeographic analysis under the Dispersal Extinction Cladogenesis (DEC) model, in order to estimate the historical ranges and patterns of dispersal across the genus. The results of the biogeographic analysis supported this historical north to southeast movement. In conjunction with our diversification estimates, our DEC results suggest that climatic events such as cooling during the Miocene and Pliocene may have shaped the divergence and current distributions in Xenosaurus.

A Taxonomic Revision of the Amazonian Genus Dicorynia (Fabaceae: Dialioideae)

Dicorynia stands out among the 17 genera of the diverse legume subfamily Dialioideae as an example of extreme floral reduction and specialization. It has asymmetric flowers presenting a heteromorphic calyx, trimerous corolla, and pair of highly dimorphic stamens, with one or both anthers polysporangiate. The two species of Dicorynia are Amazonian trees, one of which is highly valued for its timber. Despite the economic importance of the genus and an abundance of new collections, no comprehensive taxonomic study of Dicorynia has been completed since the publication of Koeppen’s monograph almost six decades ago, in which two species were recognized, one of which divided into six varieties. The present work employs integrative analysis of geographical, ecological, and extensive specimen-based morphological data to test previous delimitations of species and varieties. A new classification is adopted in an updated and comprehensive taxonomic revision of Dicorynia. We maintain two morphologically distinct and geographically separated species, D. guianensis and D. paraensis. The former is restricted to portions of the Guiana Shield north of the Amazon basin. At the same time, the latter is broadly distributed in the Amazon basin, but mainly north of the Amazon River. We recognize several taxonomically significant entities within the latter species, which, because they display limited morphological overlap and substantial geographical sympatry, we treat as varieties. However, we reduce the number of varieties from six to four. The taxonomic treatment contains new descriptions and illustrations, distribution maps, including two new areas of occurrence, conservation status assessments for all treated taxa, and identification keys to distinguish them. Nomenclatural, biogeographical, and ecological comments, including two new lectotypifications, are provided.

Recovered microbiome of an oviparous lizard differs across gut and reproductive tissues, cloacal swabs, and faeces.

Microbial diversity and community function are related, and can be highly specialized in different gut regions. The cloacal microbiome of Sceloporus virgatus females provides antifungal protection to eggshells, a specialized function that suggests a specialized microbiome. Here, we describe the cloacal, intestinal, and oviductal microbiome from S. virgatus gravid females, adding to growing evidence of microbiome localization in reptiles and other taxa. We further assessed whether common methods for sampling gastrointestinal (GI) microbes - cloacal swabs and faeces - provide accurate representations of these microbial communities. We found that different regions of the gut had unique microbial communities. The cloacal microbiome showed extreme specialization averaging 99% Proteobacteria (Phylum) and 83% Enterobacteriacaea (Family). Enterobacteriacaea decreased up the GI and reproductive tracts. Cloacal swabs recovered communities similar to that of lower intestine and cloacal tissues. In contrast, faecal samples had much higher diversity and a distinct composition (common Phyla: 62% Firmicutes, 18% Bacteroidetes, 10% Proteobacteria; common families: 39% Lachnospiraceae, 11% Ruminococcaceae, 11% Bacteroidaceae) relative to all gut regions. The common families in faecal samples made up <1% of cloacal tissue samples, increasing to 43% at the upper intestine. Similarly, the common families in gut tissue (Enterobacteriaceae and Helicobacteraceae) made up <1% of the faecal microbiome. Further, we found that cloacal swabs taken shortly after defaecation may be contaminated with faecal matter. Our results serve as a caution against using faeces as a proxy for GI microbes, and may help explain high between-sample variation seen in some studies using cloacal swabs.

Mitogenomic analysis of extant condor species provides insight into the molecular evolution of vultures

The evolution of large vultures linked to mountainous habitats was accompanied by extreme physiological and behavioral specializations for energetically efficient flights. However, little is known on the genetic traits associated with the evolution of these obligate soaring scavengers. Mitochondrial DNA plays a vital role in regulating oxidative stress and energy production, and hence may be an important target of selection for flight performance. Herein, we characterized the first mitogenomes of the Andean and California condors, the world’s heaviest flying birds and the only living representatives of the Vultur and Gymnogyps genus. We reconstructed the phylogenetic relationships and evaluated possible footprints of convergent evolution associated to the life-history traits and distributional range of vultures. Our phylogenomic analyses supported the independent evolution of vultures, with the origin of Cathartidae in the early Paleogene (~ 61 Mya), and estimated the radiation of extant condors during the late Miocene (~ 11 Mya). Selection analyses indicated that vultures exhibit signals of relaxation of purifying selection relative to other accipitrimorph raptors, possibly indicating the degeneration of flapping flight ability. Overall, our results suggest that the extreme specialization of vultures for efficient soaring flight has compensated the evolution of large body sizes mitigating the selection pressure on mtDNA.

Evolution Towards Fossoriality and Morphological Convergence in the Skull of Spalacidae and Bathyergidae (Rodentia)

Rodents show a wide range of anatomical, physiological, and behavioral adaptations to life underground. Cranial and postcranial bone morphologies are deeply impacted by the modes of digging, which can involve either incisors or claws. However, the morphological variation of these elements still needs to be accurately quantified to assess the degree of specializations of the fossorial rodent families in regards to their respective evolution. Here, we focus on the morpho-functional characteristics of the masticatory apparatus in two families of subterranean rodents, the Spalacidae and Bathyergidae. We quantify skull shape in five spalacid genera using geometric morphometric methods, as well as biomechanical estimates for adductor muscles, which are compared with data previously published on bathyergids. We show that skull shape of spalacids has a greater disparity and lower biomechanical estimates than bathyergids, in which the fossorial activity, notably chisel-tooth digging, more significantly impacted the evolution of the skull. Among spalacids, Spalax shows the most extreme specializations to life underground and displays the highest number of morphological convergences with chisel-tooth digging bathyergids, especially regarding its cranial shape and high biomechanical estimate for the temporalis muscle. Fewer morphological convergences were observed between other spalacids and bathyergids. Different evolutionary histories can potentially explain discrepancies observed between the two families, the first bathyergid morphological adaptations to fossorial life being much older than those of spalacids.

Code Is Your Partner in Thought

Writing about the buildup of technical debt, Ward Cunningham said, “Although immature code may work fine and be completely acceptable to the customer, excess quantities will make a program unmasterable, leading to extreme specialization of programmers and finally an inflexible product.” In this article, I’ll dig into the apparent paradox: how can code work fine and yet be unmasterable? Our code has characteristics of both a machine and pure thought. Technical debt arises when these do not line up. Software developers have a hard time seeing how weird this is because we’re too familiar with our subject. To help us see it from a nonprogrammer perspective, I’m going to try something a bit different in this column. What follows is a fictional conversation between me and a nonprogrammer friend.

Degradation of key photosynthetic genes in the critically endangered semi-aquatic flowering plant Saniculiphyllum guangxiense (Saxifragaceae)

BackgroundPlastid gene loss and pseudogenization has been widely documented in parasitic and mycoheterotrophic plants, which have relaxed selective constraints on photosynthetic function. More enigmatic are sporadic reports of pseudogenization and loss of important photosynthesis genes in lineages thought to be fully photosynthetic. Here we report the complete plastid genome of Saniculiphyllum guangxiense, a critically endangered and phylogenetically isolated plant lineage, along with genomic evidence of reduced chloroplast function. We also report 22 additional plastid genomes representing the diversity of its containing clade Saxifragales, characterizing gene content and placing variation in a broader phylogenetic context.ResultsWe find that the plastid genome of Saniculiphyllum has experienced pseudogenization of five genes of the ndh complex (ndhA, ndhB, ndhD, ndhF, and ndhK), previously reported in flowering plants with an aquatic habit, as well as the surprising pseudogenization of two genes more central to photosynthesis (ccsA and cemA), contrasting with strong phylogenetic conservatism of plastid gene content in all other sampled Saxifragales. These genes participate in photooxidative protection, cytochrome synthesis, and carbon uptake. Nuclear paralogs exist for all seven plastid pseudogenes, yet these are also unlikely to be functional.ConclusionsSaniculiphyllum appears to represent the greatest degree of plastid gene loss observed to date in any fully photosynthetic lineage, perhaps related to its extreme habitat specialization, yet plastid genome length, structure, and substitution rate are within the variation previously reported for photosynthetic plants. These results highlight the increasingly appreciated dynamism of plastid genomes, otherwise highly conserved across a billion years of green plant evolution, in plants with highly specialized life history traits.

Extremely divergent host plant acceptance with gene flow between sympatric host races of the phytophagous ladybird beetle Henosepilachna diekei

AbstractEcological divergence alone can prevent the majority of gene flow in the absence of other forms of reproductive isolation. Although the importance of ecological divergence in promoting reproductive isolation has been broadly recognized, its net impact on speciation has rarely been estimated in the wild. The phytophagous ladybird beetle Henosepilachna diekei Jadwiszczak &amp; Wegrzynowicz includes two sympatric host races that are reproductively isolated solely by extreme specialization to either of the host plants Mikania micrantha Kunth (Asteraceae) or Leucas lavandulifolia Sm. (Lamiaceae) in West Java, Indonesia. To investigate the impact of differential host use as an isolating barrier, we carried out adult host acceptance tests and molecular population genetic analyses based on mitochondrial ND2 and nucleic ITS2 gene sequences using 13 wild populations of the host races, including four sympatric population pairs. Almost all individuals of these host races persistently accepted only the original host plant. We detected restricted but a degree of gene flow between these host races. A migration event occurred only in very recent time compared to their divergence time, indicating recent secondary contact of these host races in the surveyed area. These results reveal the remarkably large impact of host‐plant shift over almost the entire process of speciation and illustrate that ecological divergence has been maintained even under the presence of a certain degree of gene flow.

Expansão do cultivo de cana-de-açúcar em Mato Grosso do Sul: a crise da usina São Fernando e implicações territoriais na região de Dourados (MS)

Neste trabalho analisamos a expansão da produção da cana-de-açúcar em Mato Grosso do Sul, em uma tentativa de compreender as implicações territoriais relativas ao funcionamento de uma usina do setor sucroenergético em um município. A recente instalação de inúmeras usinas em Mato Grosso do Sul, acompanhando uma nova expansão do setor sucroenergético, trouxe ao mesmo tempo desenvolvimento econômico e uma certa vulnerabilidade social nos municípios envolvidos com produção de cana-de-açúcar. Assim, almejamos entender o impacto do setor sucroenergético em uma região, abordando o caso da instalação e falência da usina São Fernando na cidade de Dourados, buscando compreender o impacto nos serviços terceirizados, terras arrendadas, conflitos em terras indígenas e insegurança na contratação de mão de obra da população local. São considerações acerca da extrema concentração do plantio da cana-de-açúcar nos municípios do sul do estado, o que só aprofunda a situação atual de extrema especialização produtiva, definida pela produção de commodities selecionadas para exportação.

Division of labor and brain evolution in insect societies: Neurobiology of extreme specialization in the turtle ant Cephalotes varians.

Strongly polyphenic social insects provide excellent models to examine the neurobiological basis of division of labor. Turtle ants, Cephalotes varians, have distinct minor worker, soldier, and reproductive (gyne/queen) morphologies associated with their behavioral profiles: small-bodied task-generalist minors lack the phragmotic shield-shaped heads of soldiers, which are specialized to block and guard the nest entrance. Gynes found new colonies and during early stages of colony growth overlap behaviorally with soldiers. Here we describe patterns of brain structure and synaptic organization associated with division of labor in C. varians minor workers, soldiers, and gynes. We quantified brain volumes, determined scaling relationships among brain regions, and quantified the density and size of microglomeruli, synaptic complexes in the mushroom body calyxes important to higher-order processing abilities that may underpin behavioral performance. We found that brain volume was significantly larger in gynes; minor workers and soldiers had similar brain sizes. Consistent with their larger behavioral repertoire, minors had disproportionately larger mushroom bodies than soldiers and gynes. Soldiers and gynes had larger optic lobes, which may be important for flight and navigation in gynes, but serve different functions in soldiers. Microglomeruli were larger and less dense in minor workers; soldiers and gynes did not differ. Correspondence in brain structure despite differences in soldiers and gyne behavior may reflect developmental integration, suggesting that neurobiological metrics not only advance our understanding of brain evolution in social insects, but may also help resolve questions of the origin of novel castes.

Tecnologías de la Comunicación y posverdad: implicaciones para la gestión de la Comunicación Hospitalaria

La forma en la que la necesidad y la gestión del conocimiento nos ha llevado a ordenar nuestra visión del conocimiento es mediante la especialización. Una especialización en ocasiones extrema que nos lleva muy a menudo a tener que cruzar especialidades de formas que se nos antojan extrañas, pero que vemos sobre todo en materias de carácter transversal, tendentes a cruzar sus caminos en múltiples campos de experiencia. Una de tales materias es la comunicación, sobre todo a raíz de la implementación de las TIC, que han forzado a instituciones y particulares a ampliar y repensar el modo en el que nos comunicamos, la cantidad de información que transmitimos y como de a menudo la transmitimos. La sociedad se está acostumbrando a un grado de interactividad y de acceso inmediato a la información que obliga a los responsables de comunicación institucional a adaptarse al ritmo o caer en la irrelevancia. Siendo como son, responsables en buena medida de los intereses de la entidad de cara al público, precisan de combinar los valores y la circunstancia de los centros en los que trabajan (en este caso, los sanitarios) con esta nueva realidad. Y una tarea que puede convertirse en bandera y medio de esta labor, es la lucha dentro de su terreno, contra el fenómeno de la posverdad.

Are you Serious

Extreme specialization will require us to replace generic conceptions of autonomy with discipline-specific methods of assessing whether one has matters in hand, is acting in earnest, and can be taken seriously. The uniform personality structures predominantly discussed in recent moral philosophy will not do; however, solutions to the problems of cross-disciplinary quality control will have to figure into those assessments. This sort of quality control cannot be managed by having experts explain themselves to nonexperts, but checking for refractive equilibrium across areas of expertise may do much of the job.