Relative Roles Research Articles

What Predicts Gene Flow During Speciation? The Relative Roles of Time, Space, Morphology and Climate.

The processes that restrict gene flow between populations are fundamental to speciation. Here, we develop a simple framework for studying whether divergence in morphology, climatic niche, time and space contribute to reduced gene flow among populations and species. We apply this framework to a model system involving a clade of spiny lizards (Sceloporus) occurring mostly in northeastern Mexico, which show striking variation in morphology and habitat among closely related species and populations. We developed a new time-calibrated phylogeny for the group using RADseq data from 152 individuals. This phylogeny identified 12 putative species-level clades, including at least two undescribed species. We then estimated levels of gene flow among 21 geographically adjacent pairs of species and populations. We also estimated divergence in morphological and climatic niche variables among these same pairs, along with divergence times and geographic distances. Using Bayesian generalised linear models, we found that gene flow between pairs of lineages is negatively related to divergence time and morphological divergence among them (which are uncorrelated), and not to geographic distance or climatic divergence. The framework used here can be applied to study speciation in many other organisms having genomic data but lacking direct data on reproductive isolation. We also found several other intriguing patterns in this system, including the parallel evolution of a strikingly similar montane blue-red morph from more dull-coloured desert ancestors within two different, nonsister species.

Decreased DNA density is a better indicator of a nuclear bleb than lamin B loss.

Nuclear blebs are herniations of the nucleus that occur in diseased nuclei that cause nuclear rupture leading to cellular dysfunction. Chromatin and lamins are two of the major structural components of the nucleus that maintain its shape and function, but their relative roles in nuclear blebbing remain elusive. To determine the composition of nuclear blebs, we compared the immunofluorescence intensity of DNA and lamin B in the main nucleus body to the nuclear bleb across cell types and perturbations. DNA density in the nuclear bleb was consistently decreased to about half of the nuclear body while lamin B levels in the nuclear bleb varied widely. Partial Wave Spectroscopic (PWS) microscopy recapitulated significantly decreased likelihood of high-density domains in the nuclear bleb versus body, independent of lamin B. Time lapse imaging into immunofluorescence reveals that decreased DNA density marks all nuclear blebs while decreased lamin B1 levels only occur in blebs that have recently ruptured. Thus, decreased DNA density is a better marker of a nuclear bleb than lamin B level.

Impacts of the Arctic Stratospheric Polar Vortex Weakening on Ural Blocking in Boreal Winter

AbstractUsing the ERA5 reanalysis data, we analyzed the impacts of the Arctic stratospheric polar vortex weakening on Ural Blocking (UB). The results indicate that UB activities are suppressed following the weakening of the polar vortex. Specifically, the probability of UB is significantly reduced, with a maximum decrease of 30% observed around day 24 following the polar vortex weakening. The average life cycle of UB shortens by approximately one day. The amplitude of UB, as measured by the negative potential vorticity (PV) anomalies over the Urals, experiences a significant decrease, particularly with the presence of positive PV anomalies on the western side of Urals. Further analysis indicates that the suppression of UB following the weakened polar vortex is closely linked to both the equatorward horizontal transport of high‐PV air over the Arctic across the dynamic tropopause, and the anomalous increase in static stability over the Urals resulting from a descent of the isentropic surface near the tropopause. Finally, we evaluate the relative roles of the polar vortex weakening and the negative phase of the Arctic Oscillation (AO) in suppressing the development of UB. Our analysis reveals that the impacts of the weak polar vortex on the suppression of UB are stronger and more long‐lasting compared to the negative AO, suggesting that the impacts of the weakened polar vortex on UB cannot be simply explained by the AO response.

Middle-Level Teacher Development and Identity: A Review of the Literature

Historically, the field of middle-level education has taken it as a given that teachers of young adolescents should be specially prepared to teach in the middle grades, developing a teacher identity that centers around responding to and advocating for the age group above an identity as a subject area teacher. Defined broadly as teachers’ dynamic conceptualizations of themselves as educators and their related roles, decisions, and actions, teacher professional identity has garnered considerable attention in the research literature as a potential source of leverage in multiple dimensions of schooling, preservice teacher education and in-service teachers’ professional learning, and teachers’ professional lives. Teacher identity at the middle level is ideally grounded in a deep commitment to helping young adolescents realize their power and possibilities. While the literature on teacher identity development is well-established in some educational contexts, studies specifically examining the potentially unique developmental trajectory of teacher identity among middle-level educators remain limited. To address this gap, we conducted a review of the literature to address the question: what does the research say about middle-level teacher development and identity? Our review identified 26 relevant sources on middle-level teacher development and identity, published from 2015 through the first half of 2024, and yielded key ideas within three themes: (a) the development of teacher identity, (b) the intersectionality of teacher identity, and (c) critical consciousness, agency, and teacher identity. This review identifies both progress and gaps in the current literature, recognizes potential future directions for research on middle-level teacher identity, and offers possible implications for preservice and in-service middle-level teacher education.

Tourism metagovernance and the role of the state: Insights from post-blast Beirut

This paper examines the institutionalised interests and values that underpin tourism governance (i.e., tourism metagovernance), to explain why certain governance arrangements appear and how they function. We examined the redevelopment of Beirut's tourism-dependent Mar Mikhael and Gemmayze neighbourhoods in the aftermath of the 2020 port blast. The chaotic post-disaster setting reflected and amplified the ineffectiveness of the already existing, strongly intertwined, metagovernance of urban development and urban tourism in Beirut. The state's absence resulted in enhanced community vulnerability, uncoordinated donor-led disaster responses, and limited strategic rebuilding of tourism and cultural activities. Even when the state as a key governance intermediary is absent, its relational and institutional roles affect tourism metagovernance and, therefore, influence the resilience of tourism governance and development.

CHEX-MATE: The intracluster medium entropy distribution in the gravity-dominated regime

We characterise the intracluster gas entropy profiles of 32 very high-mass ($M_ $ M$_ odot Planck SZ-detected galaxy clusters (HIGHMz), selected from the CHEX-MATE sample, allowing us to study the intracluster medium (ICM) entropy distribution in a regime where non-gravitational effects are expected to be minimised. Using XMM- Newton measurements, we determined the entropy profiles up to $ $ for all objects. We assessed the relative role of gas density and temperature measurements on the uncertainty in entropy reconstruction, showing that in the outer regions the largest contribution comes from the temperature. The scaled profiles exhibit a large dispersion in the central regions, but converge rapidly to the value expected from simple gravitational collapse beyond the core regions. We quantified the correlation between the ICM morphological parameters and scaled entropy as a function of radius, showing that centrally peaked objects have low central entropy, while morphologically disturbed objects have high central entropy. We compared the scaled HIGHMz entropy profiles to results from other observational samples, finding differences in normalisation, which appear linked to the average mass of the samples in question. Combining HIGHMz with other samples, we found that a weaker mass dependence than self-similar in the scaling ($A_m -0.25$) allows us to minimise the dispersion in the radial range $ for clusters spanning over a decade in mass. The deviation from self-similar predictions is radially dependent and is more pronounced at small and intermediate radii than at $R_ $. We also investigated the distribution of central entropy $K_0$, finding no evidence for bimodality in the data and outer slope alpha , which peaks at $ 1.1$ with tails at both low and high alpha that correlate with dynamical state. Using weak-lensing masses for half of the sample, we found an indication for a small suppression of the scatter ($ beyond the core when using masses derived from $Y_X$ in the rescaling. Finally, we compared our results to recent cosmological numerical simulations from HE T HREE H UNDRED and MACSIS, finding good agreement with the observational data in this mass regime. These results provide a robust observational benchmark in the gravity-dominated regime, and will serve as a future reference for samples at lower masses, higher redshifts, and for ongoing work using cosmological numerical simulations.

A framework for training graduate students and campus communities in inclusive teaching.

While graduate student teaching assistants (TAs) contribute significantly to university education, many graduate programs across diverse disciplines offer limited formal pedagogical training. In turn, many researchers informally develop teaching and mentoring skills as they advance to faculty positions or related careers. This can perpetuate a lag in the implementation of inclusive educational environments despite the clear benefits demonstrated by recent pedagogical research. For instance, the integration of inclusive teaching strategies like universal design for learning, growth mindset feedback, and the use of relatable role models in curricula may help increase the persistence, success, and self-efficacy of traditionally underrepresented groups in the sciences. Additionally, research indicates that training graduate TAs in evidence-based practices may have benefits beyond teaching efficacy, such as greater confidence in research preparedness and science communication-skills applicable to any scientific field or career path. Here, we developed and implemented an inclusive teaching series for a marine science department that included: (i) campus-wide pedagogical journal article discussions and knowledge-sharing, (ii) expert-led interactive workshops on evidence-based teaching strategies, and (iii) a graduate TA professional development module on inclusive lesson planning with opportunities to teach and receive feedback. Based on our experiences, we share a framework and resources to facilitate a broader adoption of formalized TA training in inclusive teaching practices within graduate programs across a variety of fields.

Modulating TTN gene expression in human iPSC-CMs to investigate mechanisms and therapies in TTN-associated dilated cardiomyopathy

Abstract Background Familial dilated cardiomyopathy (DCM) is a common and harmful condition, and no available therapies target the underlying genetic mechanisms. Truncating variants in TTN are the most commonly identified genetic cause of DCM. However, it remains unclear how TTN variants drive disease. Contemporary thinking identifies haploinsufficiency, dominant negative effects, or a combination of both as likely driving mechanisms. There is competing evidence as to whether I-band and A-band mutations differ in severity or in the relative roles of haploinsufficiency and dominant-negative effects. Clarifying disease mechanisms will help pave the way to targeted genetic therapies. Purpose To modulate TTN gene expression in human-induced stem cell-derived cardiomyocyte (hiPSC-CM) models of TTN-associated DCM carrying I-band or A-band variants to provide insight into the comparative roles of haploinsufficiency and dominant negative mechanisms in DCM, and to identify novel therapeutic strategies. Methods We used CRISPR-Cas9 gene-editing to generate hiPSC lines with known disease-causing heterozygous truncating mutations in the I-band or A-band of TTN. These were screened for off-target mutations and pluripotency. hiPSCs were differentiated into hiPSC-CMs for phenotyping. We assayed TTN mRNA and titin protein levels. We trialled approaches for modulating TTN expression including CRISPR activation. Results Two hiPSC lines with heterozygous mutations in the I-band and A-band of TTN were generated using CRISPR/Cas-9 gene-editing. These hiPSC lines were successfully differentiated into hiPSC-CMs. Both cell lines demonstrated unchanged TTN mRNA expression compared to wildtype controls, but had reduced expression of full-length titin protein and identifiable truncated protein products. TTN mRNA expression was subsequently increased in these models using modulators of gene expression. Conclusions hiPSC-CM models of DCM with truncating mutations in the I-band or A-band of TTN were generated and phenotyped. These models were then used to trial gene expression modulation methods. This provides a human cellular system that can be used to better understand disease mechanisms of TTN-associated DCM, with the ultimate aim of establishing gene therapies for TTN-associated DCM.

Hybrid Raman and Partial Wave Spectroscopy Microscope for the Characterization of Molecular and Structural Alterations in Tissue.

We present a hybrid Raman spectroscopy (RS) and partial wave spectroscopy (PWS) microscope for the characterization of molecular and structural tissue alterations. The PWS performance was assessed with surface roughness standards, while the Raman performance with a silicon crystal standard. We also validated the system on stomach and intestinal mouse tissues, two closely-related tissue types, and demonstrate that the addition of PWS information improves RS data classification for these tissue types from R2 = 0.892 to R2 = 0.964 (norm of residuals 0.863 and 0.497, respectively). Then, in a proof-of-concept experiment, we show that the hybrid system can detect changes in intestinal tissues harvested from a tumorigenic Villin-Cre, Apcfl/wt mouse. We discuss how the hybrid modality offers new abilities to identify the relative roles of PWS morphological features and Raman molecular fingerprints, possibly allowing for their combination to enhance the study of carcinogenesis and early cancer diagnostics in the future.

Environment, plant genetics, and their interaction shape important aspects of sunflower rhizosphere microbial communities.

Associations with soil microorganisms are crucial for plants' overall health and functioning. While much work has been done to understand drivers of rhizosphere microbiome structure and function, the relative importance of geography, climate, soil properties, and plant genetics remains unclear, as results have been mixed and comprehensive studies across many sites and genotypes are limited. Rhizosphere microbiomes are crucial for crop resistance to pathogens, stress tolerance, nutrient availability, and ultimately yield. Here, we quantify the relative roles of plant genotype, environment, and their interaction in shaping soil rhizosphere communities, using 16S and ITS gene sequencing of rhizosphere soils from 10 genotypes of cultivated sunflower (Helianthus annuus) at 15 sites across the Great Plains of the United States. While site generally outweighed genotype overall in terms of effects on archaeal, bacterial, and fungal richness, community composition, and taxa relative abundances, there was also a significant interaction such that genotype exerted a significant influence on archaeal, bacterial, and fungal microbiomes in certain sites. Site effects were attributed to a combination of spatial distance and differences in climate and soil properties. Microbial taxa that were previously associated with resistance to the fungal necrotrophic pathogen Sclerotinia were present in most sites but differed significantly in relative abundance across sites. Our results have implications for plant breeding and agronomic microbiome manipulations for agricultural improvement across different geographic regions.IMPORTANCEDespite the importance of plant breeding in agriculture, we still have a limited understanding of how plant genetic variation shapes soil microbiome composition across broad geographic regions. Using 15 sites across the Great Plains of North America, we show that cultivated sunflower rhizosphere archaeal, bacterial, and fungal communities are driven primarily by site soil and climatic differences, but genotype can interact with site to influence the composition, especially in warmer and drier sites with lower overall microbial richness. We also show that all taxa that were previously found to be associated with resistance to the fungal pathogen Sclerotinia sclerotiorum were widespread but significantly affected by site, while a subset was also significantly affected by genotype. Our results contribute to a broader understanding of rhizosphere archaeal, bacterial, and fungal community assembly and provide foundational knowledge for plant breeding efforts and potential future microbiome manipulations in agriculture.

Multivariate Cluster Point Process to Quantify and Explore Multi-Entity Configurations: Application to Biofilm Image Data.

Clusters of similar or dissimilar objects are encountered in many fields. Frequently used approaches treat each cluster's central object as latent. Yet, often objects of one or more types cluster around objects of another type. Such arrangements are common in biomedical images of cells, in which nearby cell types likely interact. Quantifying spatial relationships may elucidate biological mechanisms. Parent-offspring statistical frameworks can be usefully applied even when central objects ("parents") differ from peripheral ones ("offspring"). We propose the novel multivariate cluster point process (MCPP) to quantify multi-object (e.g., multi-cellular) arrangements. Unlike commonly used approaches, the MCPP exploits locations of the central parent object in clusters. It accounts for possibly multilayered, multivariate clustering. The model formulation requires specification of which object types function as cluster centers and which reside peripherally. If such information is unknown, the relative roles of object types may be explored by comparing fit of different models via the deviance information criterion (DIC). In simulated data, we compared a series of models' DIC; the MCPP correctly identified simulated relationships. It also produced more accurate and precise parameter estimates than the classical univariate Neyman-Scott process model. We also used the MCPP to quantify proposed configurations and explore new ones in human dental plaque biofilm image data. MCPP models quantified simultaneous clustering of Streptococcus and Porphyromonas around Corynebacterium and of Pasteurellaceae around Streptococcus and successfully captured hypothesized structures for all taxa. Further exploration suggested the presence of clustering between Fusobacterium and Leptotrichia, a previously unreported relationship.

Experimental species removal reveals species contributions to positive pollinator-mediated reproductive interactions.

Pollinator-mediated reproductive interactions among co-flowering plant species provide a canonical example of how biotic factors may contribute to species coexistence, yet we lack understanding of the exact mechanisms. Flowering-dominant and unusually attractive "magnet species" with disproportionate contributions to pollination may play key roles in such reproductive interactions, but their relative roles within the same community have rarely been assessed. We experimentally removed either a flowering-dominant or a highly attractive magnet species and compared effects on visitation frequency, pollinator richness, and seed set of co-flowering plants. Removal of either the flowering-dominant species or the magnet species reduced community-level pollinator visitation. Removal of the magnet species had the most consistent effect, including reduced pollinator visitation and richness, and reduced seed set of most co-flowering plants. These results suggest that the magnet species, which interacts with a wider range of pollinator species than does the dominant species, promotes the visitation and reproductive fitness of most other species. Removal of the flowering-dominant species affected only certain species, perhaps because these plants had floral traits similar to the dominant species. Our results highlight the role of attractive magnet species within a community in structuring reproductive interactions and identify potential mechanisms involved in coexistence facilitated by reproductive interactions.

Beyond greenhouse gases – Comprehensive planetary boundary footprints to measure environmental impact

The planetary boundary framework identifies nine areas of key environmental risk globally. The causes of climate change are well understood as a serious and existential threat; however the other eight areas of concern have a much more limited understanding of what is driving their continued increase.This research utilises Global Resource Input Output Assessment (GLORIA) multiregional input-output (MRIO) tables to map 15 footprint indicators across 51 sectors and seven global regions, identifying key sectors driving planetary boundary impacts and suggesting targeted interventions for sustainability.The relative role of emission intensity and total expenditure is shown, and potential trade-offs and synergies between sectors and indicators are identified. High-impact footprint clusters are identified as food and textiles, and the built environment, with moderate impacts from the services and energy sectors. These relationships are compared to several transformation agendas, identifying overlooked relationships and drivers, including the predominant role of commercial buildings and infrastructure in built environment impacts and the correlation between greenhouse gas emissions and air pollution. The primary driver of plastic use footprints is seen to be the built environment, however as a whole chemical pollution levels remain a significant unknown, and the challenge to globally stop the flow of further dangerous substances and clean up existing contaminated sites is large.By providing a detailed breakdown of planetary boundary drivers this work enables decision-makers to understand the risks and issues associated with economic purchases across all critical environmental pathways simultaneously to better prioritise action for a stable planet.

Impacts of land use and abiotic factors on fruit, seed, and leaf morphology of the desert date Balanites aegyptiaca in Benin: Implications for management

Preserving intraspecific phenotypic variation within socio-economically important but declining species is fundamental in the current context of rapid change in land use and environmental conditions. Balanites aegyptiaca (L.) Delile is a valuable seed oil tree species native to the arid and semi-arid regions of Africa. Notable morphological variations within the species are recognized by local communities, who often select trees with preferred traits for preservation in croplands. This study compared phenotypic variation in B. aegyptiaca based on sixteen phenotypic traits of fruits, seeds, and leaflets between trees in a strictly protected area and those in croplands. Furthermore, the relative role of land use, soil characteristics, bioclimatic variables, elevation, and slope in the observed variation was analysed. Student t-test, principal component analysis, redundancy analysis, and variance partitioning were used for data analysis in R software. Results showed that, after accounting for tree variation, significant differences were observed in only two traits: seed ratio, and leaflet dry weight, with mean values in cropland being 1.470 (higher), and 0.943 (lower) times that of wild trees, respectively. Furthermore, principal component analysis showed great overlap between ellipses of cropland and wild trees. The variance partitioning analysis showed that bioclimatic variables explained 18 % of the total variation followed by soil characteristics (11 %), and land use (9 %). These findings collectively suggest weak impacts of croplands and a lack of domestication syndrome in B. aegyptiaca in Benin, potentially due to persisting gene flow between wild and cropland trees, inadvertent species management, or low intensity of selection pressures. Future studies should explore organoleptic properties, physico-chemical characteristics of the pulp and seed oil and discern the extent to which observed differences are attributable to genetic factors and biotic factors (pest attacks, plant-plant interactions, etc.).

In plain sight: Mechanisms of means-ends decoupling in impact investing

Impact investors are supposed to generate financial returns alongside social and environmental benefits. Increasingly, they must also measure these benefits as a form of performance management to provide robust evidence of impact. However, it is an “open secret” that because of inconsistencies and fragmentation in the applied means of impact measurement, ends are imperfectly met. In this article, we probe how and why means-ends decoupling occurs in impact investing in plain sight. We apply a qualitative and interpretative approach, drawing on 135 interviews and 102 documents gathered from impact investors. We find that impact measurement is not primarily used for performance management but plays a relational role between stakeholders. We uncover and conceptualize three mechanisms that drive decoupling between the ideal and actual functions of impact measurement, namely impact measurement as: (1) communication, (2) categorization, and (3) construction of the domain. We also find an important contingency: decoupling becomes more likely with increasing systemic opacity in an investment field. We outline contributions to the organizational decoupling literature and the sociology of quantification, and we show how the problems that arise from means-ends decoupling could be overcome.

Evaluation of Hepatitis C Virus Transmission Through Endoscopy Procedures in the Country of Georgia.

Exposure to healthcare procedures might be a source of hepatitis C virus (HCV) transmission in Georgia, one of the few countries currently on track to eliminate hepatitis C. While there has been a history of iatrogenic transmission of HCV, the risk of HCV transmission related to endoscopic procedures has not been previously assessed in Georgia. The goal of this study was to assess HCV seroconversion among individuals undergoing endoscopic procedures to estimate the relative role and incidence of HCV infection attributable to endoscopic procedures. A prospective cohort study was conducted in four endoscopy units in two cities (Tbilisi and Kutaisi) of Georgia during April-September, 2021. Recruitment of study participants was conducted using convenience sampling, and every eligible patient was approached and invited to participate in the study. Study population included adults (age ≥ 18 years) who received an endoscopic procedure (gastroscopy, colonoscopy and bronchoscopy) in inpatient or outpatient unit at the study sites. HCV antibody (anti-HCV) testing was conducted using rapid diagnostic test (RDT) on the same day they underwent the endoscopic procedure. Patients with a non-reactive anti-HCV baseline test were retested after 6 months. Patients with reactive baseline tests were excluded from the study and linked to further testing and care. Participants with a reactive result on follow-up RDTs were retested using a lab-based anti-HCV and HCV ribonucleic acid (RNA) test. A total of 981 HCV antibody non-reactive participants were enrolled; 590 (64.8%) of them were reached and retested after 6 months. At retesting, two out of 590 (0.3%) individuals had a reactive anti-HCV result on RDT and both were negative on laboratory-based anti-HCV and HCV RNA tests. Based on the results of this study, endoscopic procedures were not shown to contribute to HCV transmission in Georgia.

In Search of the Causes of the Globalization Backlash: Methodological Considerations on Post-treatment Bias

We study the implications of post-treatment bias in the context of the globalization backlash. We discuss whether horse-race regressions can inform about the relative role of economic versus cultural drivers. We make three methodological points: (1) if and insofar as cultural variables are post-treatment with respect to economic factors, the estimates of the effect of economic shocks on voting are biased in regressions that include cultural controls (and vice versa); (2) for the same reason, such horse-race regressions do not allow to accurately estimate the relative role of economic versus cultural factors; (3) one cannot infer mediation effects from changes in regression coefficients for a given factor of interest before and after including post-treatment controls. We accompany the methodological discussion with empirical evidence on the relevance of post-treatment bias in studies of the globalization backlash, both by replicating and expanding on earlier studies, and by presenting novel cross-country results on the culture-economy nexus.

Postpartum periods of visually impaired mothers: A qualitative study.

Parenting for individuals with visual impairments introduces unique challenges, requiring meticulous planning, attention and care in daily activities and child-rearing. This qualitative study aims to explore the postpartum experiences of visually impaired mothers, exploring their emotional challenges, support networks and experiences in caring for infants and breastfeeding. Twelve participants engaged in in-depth interviews, revealing emotional difficulties such as uneasiness, anxiety, fear and challenges in baby care. The study highlights the pivotal role of family, spouses and relatives in providing crucial support, contributing significantly to overcoming challenges related to childcare and breastfeeding. Supportive family involvement emerged as a key factor in meeting the emotional needs of visually impaired mothers during the postpartum period, fostering confidence in baby care and breastfeeding and transforming the experience into a more positive one. The findings highlight the importance of understanding and addressing the postpartum experiences of visually impaired mothers, advocating for more effective support programs tailored to their unique needs.

Space and spatially structured environmental variables account for variation in blackfly and mayfly communities in sub-tropical South African rivers

Using aquatic invertebrate assemblages for bioassessment of streams and rivers is a fast and cost-effective approach to studying the impact of environmental stressors in aquatic ecosystems. The use of aquatic invertebrates is premised on their predictable responses to environmental stressors. Assemblage structure is not, however, only influenced by environment, but also neutral processes and temporal variation. This study quantified the relative roles of the environment (niche processes), space (neutral processes) and temporal factors in structuring mayfly and blackfly assemblages at family and species levels. Asymmetric eigenvector maps in conjunction with canonical redundancy analysis and variation partitioning were used to explore the relative roles of these three factors in structuring macroinvertebrate assemblages. At a species level, flow and water temperature were more important in explaining assemblage structure than at the family level. At the family level, space was more important than temporal and environmental factors. Unexplained variation at species and family level was more than 50%. This suggests (i) caution in using family-level rapid assessments to infer the role of the environment in structuring aquatic macroinvertebrate assemblages, as neutral processes are also dominant; and (ii) that the importance of stochastic processes, such as dispersal, should not be underestimated in rapid assessments.

Comprehension of object relatives in Spanish: the role of frequency and transparency in acquisition and adult grammar

Abstract This study investigates the relative roles of frequency and transparency in native speakers’ comprehension of Spanish object relative sentences by comparing performance with two variants of the construction that differ in these properties. Experiment 1 suggests that seven- to eight-year-old children’s processing of object relative sentences is consistently facilitated by variant frequency and likely relies on separate representations for each variant as two different, although related constructions. Experiment 2 turns to adult comprehension of the two variants, showing similar accuracy and reaction time patterns for both variants for this population. This second outcome could be interpreted as a decrease in frequency effects over time, in line with the power law of practice, as an experience-based increase in the ability to make use of redundant markers, or both.